fix(studio): Add solid floor collision, live 3D gizmo dragging, inspector property sync, and nudge shortcuts

- Creator Studio: Visual behavior & property inspector, GLB model importer, binary persistence
- Trust & Safety: 18+ TOS confirmation (DOB removed), creator guidelines & briefing card on join, in-game reporting HUD
- Test Harness: Add --filter, --skip-backend, --skip-godot to run_checkpoint_tests.py

.gitignore

@@ -12,3 +12,7 @@ Thumbs.db
 # Godot UID files (regenerated from path)
 *.uid
 assets/build_info.json
+
+# Dynamic uploads
+uploads/
+backend/uploads/

AGENTS.md

@@ -0,0 +1,40 @@
+# ModBison (Project & Agent Guidelines)
+
+> **CRITICAL REBRANDING NOTICE**
+> - **Game Name**: **ModBison** (formerly `agp-game`).
+>   - "ModBison" represents a play on game modification and the 1960s British "mod" subculture, adhering to the user's "bison" project naming convention (e.g. host machine `cloudbison`, Windows client machine `pinkbison`, social platform `WiseBison`).
+> - **In-Game Currency**: **Buffalo Chips** (formerly `Credits` / `CR`).
+>   - Named playfully after bison poop. Displayed throughout all UI menus, wallet, marketplace, and creator payout screens as "Buffalo Chips".
+> - **Git Repository**:
+>   - Local clone path: `/home/daddy/modbison` (symlinked as `/home/daddy/agp-game-dev` for backwards compatibility).
+>   - Gitea repository name: `modbison`
+>   - Clone URL: `http://localhost:3000/daddy/modbison.git`
+>   - Web UI: `https://git.cloudbison.duckdns.org/daddy/modbison`
+> - **Binaries & Exports**:
+>   - Windows: `modbison.exe` (legacy alias `agp-game.exe` maintained for backwards compatibility)
+>   - Linux: `modbison.x86_64`
+
+---
+
+## Architecture Overview
+
+1. **Client**: Godot 4.6.2 (GDScript).
+   - Headless engine binary located at `~/godot/godot`.
+   - Export presets defined in `export_presets.cfg`.
+   - Main scenes in `res://scenes/` (`main_menu.tscn`, `world_3d.tscn`, `wallet_ui.tscn`, `marketplace_ui.tscn`, `selling_payout_ui.tscn`, etc.).
+   - Scripts in `res://scripts/`.
+
+2. **Backend**: FastAPI + SQLAlchemy (asyncpg) + Alembic in `backend/`.
+   - Python environment: `/home/daddy/agp/venv` (or project `.venv`).
+   - Runtime game server supervisor allocates headless Godot instances per active world session under `/tmp/modbison-game-servers`.
+
+3. **Orchestration & Playtesting (`/home/daddy/agp`)**:
+   - PM Dashboard: `http://localhost:7070` (`agp-dashboard.service`).
+   - Checkpoint system: `pm/checkpoint_ops.py` controls playtest instances (`PC1` through `PC5`).
+   - Current active checkpoint: **PC5** (backend on `http://192.168.58.138:28005`, postgres on `25545`).
+   - Building Windows package: `PYTHONPATH=. /home/daddy/agp/venv/bin/python3 -c "import pm.checkpoint_ops as ops; ops.build_exe('PC5')"`
+
+4. **Testing Protocols**:
+   - Headless smoke tests: `AGP_API_BASE_URL=http://127.0.0.1:28005 ~/godot/godot --headless --path . --script res://scripts/smoke_test_<name>.gd`
+   - Fast checkpoint tests: `PYTHONPATH=. /home/daddy/agp/venv/bin/python3 scripts/run_checkpoint_tests.py --skip-backend --filter <keyword>`
+   - Backend pytest: `PYTHONPATH=. /home/daddy/agp/venv/bin/pytest backend/tests`

CLAUDE.md

@@ -0,0 +1,18 @@
+# ModBison Guidelines for Claude Code
+
+See [AGENTS.md](AGENTS.md) for full project conventions.
+
+### Quick Reference:
+- **Game Name**: ModBison (formerly agp-game)
+- **Currency**: Buffalo Chips (formerly Credits / CR)
+- **Repo URL**: `http://localhost:3000/daddy/modbison.git` (`https://git.cloudbison.duckdns.org/daddy/modbison`)
+- **Working Tree**: `/home/daddy/modbison` (or `/home/daddy/agp-game-dev`)
+- **Windows Executable**: `modbison.exe`
+- **Linux Executable**: `modbison.x86_64`
+
+### Commands:
+- **Run tests**:
+  - Backend: `PYTHONPATH=. /home/daddy/agp/venv/bin/pytest backend/tests`
+  - Godot UI smoke tests: `AGP_API_BASE_URL=http://127.0.0.1:28004 ~/godot/godot --headless --path . --script res://scripts/smoke_test_<name>.gd`
+- **Rebuild PC4 Windows package**:
+  - `PYTHONPATH=. /home/daddy/agp/venv/bin/python3 -c "import pm.checkpoint_ops as ops; ops.build_exe('PC4')"`

README.md

@@ -1,3 +1,129 @@
-# agp-game
+# ModBison
 
-Agentic Game Platform - Godot game built by autonomous agents
+> **Godot 4 Multiplayer Sandbox Platform**  
+> Customizable 3D avatars, real-time multiplayer worlds, in-game building tools, social community hubs, and a creator economy powered by **Buffalo Chips**.
+
+---
+
+## 🦬 About ModBison
+
+**ModBison** (formerly `agp-game`) is a collaborative sandbox game and platform built in Godot 4 and Python FastAPI. 
+
+* **The Name**: "ModBison" is a double play on game modification and the 1960s British "mod" youth subculture, aligning with the host and infrastructure naming convention (`cloudbison`, `pinkbison`, `WiseBison`).
+* **The Currency**: **Buffalo Chips** — the in-game virtual currency used for marketplace trading, creator selling, and cash payouts (a playful reference to bison poop).
+
+---
+
+## 🏛️ Architecture Overview
+
+The platform consists of two integrated environments:
+
+1. **Client & Game Server (`modbison`)**:
+   - Built with **Godot 4.6.2** (GDScript).
+   - Headless Godot dedicated server (`scenes/server.tscn`) spawned per active world session via high ENet ports.
+   - Dual-platform export configuration: Windows Desktop (`modbison.exe`) and Linux (`modbison.x86_64`).
+   - Binary chunk streaming and client-side interpolation.
+
+2. **Backend & Orchestration Platform (`agp`)**:
+   - **FastAPI** (Python 3.12) REST API with **PostgreSQL** (asyncpg) and **Alembic** migrations.
+   - **Redis** for real-time presence heartbeats and pub/sub messaging.
+   - **Game Server Supervisor**: Dynamic headless Godot instance orchestrator allocating runtime servers in `/tmp/modbison-game-servers`.
+   - **PM Dashboard & Checkpoints**: Live orchestration dashboard running at `http://localhost:7070` managing Package Checkpoints (**PC1** through **PC4**).
+
+---
+
+## ✨ What Has Been Built (Feature Summary)
+
+### 1. 👤 3D Avatar & Customization Engine
+* **Canonical Rig**: 24-bone skeleton supporting attachment sockets for Head, Hair, Face, Chest, Pants, Left/Right Hand, Left/Right Foot, and Accessories.
+* **Customization Studio** (`scenes/avatar_customization.tscn`): Full 3D turntable preview, orbit camera controls, slot-based equipment, RGB tint pickers, and backend persistence (`/api/avatar/loadout`).
+* **Multiplayer Replication**: Remote players receive complete avatar loadout dictionaries via RPC upon joining, dynamically assembling meshes and materials in real time.
+* **Solid Double-Sided Rendering**: Fixed polygon winding order and material setups to ensure characters render fully solid from all camera angles.
+
+### 2. 🌍 Multiplayer World & Chunk Streaming
+* **Dedicated Server Architecture**: Server-authoritative player movement, client prediction, reconciliation, and collision boundaries.
+* **Chunk Streaming**: Binary stream encoding/decoding (`chunk_codec.py` / `chunk_data_decoder.gd`) enabling real-time streaming of world geometry, collision boxes, and dynamic props as players explore.
+* **Stable Spawn System**: Server-authoritative solid ground anchoring ensuring players never fall into the void upon connection.
+
+### 3. 🛠️ In-Game World Editor & Sandboxed Scripting
+* **Runtime World Editor** (`scripts/editor/`): In-game tool registry, block/prop palette, selection manager, raycast placement/deletion, and undo/redo action stacks.
+* **Chunk Persistence** (`chunk_save_service.gd`): Saves player modifications and created structures back to the world backend.
+* **Rule-Based Scripting** (`scripts/scripting/`): Sandboxed behavior interpreter (`script_interpreter.gd`, `script_rule.gd`) allowing props to trigger gameplay actions, inventory changes, and spawn events.
+* **In-Game HUD Bar**: Hotkey-driven overlay bar giving players instant access to build tools and menus while inside a live world.
+
+### 4. 👥 Social, Chat & Clans
+* **Friends & Presence** (`scenes/friends_presence_ui.tscn`): Friend requests, accept/decline flows, and live online/in-world presence heartbeats via Redis.
+* **Multi-Channel Chat** (`scenes/chat_ui.tscn`): Direct messaging (DM), group chat, and spatial in-world chat with automated text filtering (`text_filter.py`).
+* **Groups & Clans** (`scenes/groups_ui.tscn`): Group creation, member roles, descriptions, and membership rosters.
+
+### 5. 💰 Virtual Economy & Creator Payouts
+* **In-Game Currency**: **Buffalo Chips** displayed across all menus, wallets, listings, and payout screens.
+* **Wallet UI** (`scenes/wallet_ui.tscn`): Live balance display, quick-purchase packs (+100, +500, +1,000, +5,000 Buffalo Chips), and transaction history ledger.
+* **Marketplace UI** (`scenes/marketplace_ui.tscn`): Browse items for sale, filter by price in Buffalo Chips, search catalog, and instant purchase with inventory delivery.
+* **Creator Selling & Payouts** (`scenes/selling_payout_ui.tscn`): Catalog item listing, price configuration, escrow tracking (Available, In Escrow, Lifetime Earned), and cash payout requests (minimum 100 Buffalo Chips).
+
+### 6. 🌐 Discovery & Catalog
+* **World Discovery UI** (`scenes/discovery_ui.tscn`): Public world browser with search by title, tags, or category.
+* **Trending Algorithm**: Decay-weighted play counts ranking popular worlds on the discovery front page.
+
+---
+
+## 🎮 In-Game Controls & Hotkeys
+
+| Key | Action |
+| :--- | :--- |
+| **`W` `A` `S` `D`** | Move character |
+| **`Space`** | Jump |
+| **`Mouse`** | Look / Camera rotation |
+| **`T`** or **`Enter`** | Open Chat |
+| **`Tab`** or **`F1`** | Open Friends & Social Panel |
+| **`F2`** | Toggle In-Game World Editor |
+| **`ESC`** | Close current modal / Toggle In-Game HUD Menu |
+
+---
+
+## 🚀 Development, Testing & Builds
+
+### Automated Smoke Tests (Headless Godot)
+All UI panels and client subsystems have headless GDScript smoke tests:
+```bash
+# Set target backend (e.g. PC4 playtest instance)
+export AGP_API_BASE_URL=http://127.0.0.1:28004
+
+# Run individual UI & subsystem smoke tests
+~/godot/godot --headless --path . --script res://scripts/smoke_test_main_menu_full_flow.gd
+~/godot/godot --headless --path . --script res://scripts/smoke_test_marketplace_ui.gd
+~/godot/godot --headless --path . --script res://scripts/smoke_test_wallet_ui.gd
+~/godot/godot --headless --path . --script res://scripts/smoke_test_selling_payout_ui.gd
+~/godot/godot --headless --path . --script res://scripts/smoke_test_avatar_in_world.gd
+```
+
+### Backend Test Suite
+```bash
+# Run 335+ FastAPI & SQLAlchemy test suite
+PYTHONPATH=. /home/daddy/agp/venv/bin/pytest backend/tests
+```
+
+### Building Release Binaries
+```bash
+# Export Linux and Windows binaries
+scripts/build.sh
+
+# Or build pre-configured Windows package for current checkpoint (PC4):
+PYTHONPATH=. /home/daddy/agp/venv/bin/python3 -c "import pm.checkpoint_ops as ops; ops.build_exe('PC4')"
+```
+Output artifacts:
+- Windows: `export/windows/modbison.exe` (or `agp/playtest/PC4/build/windows/modbison.exe`)
+- Linux: `export/linux/modbison.x86_64`
+
+---
+
+## 📦 Project Links & Configuration
+
+* **Gitea Repository**: `http://localhost:3000/daddy/modbison.git`
+* **Web Interface**: [https://git.cloudbison.duckdns.org/daddy/modbison](https://git.cloudbison.duckdns.org/daddy/modbison)
+* **Active Playtest Instance**: **PC4**
+  - Backend URL: `http://192.168.58.138:28004`
+  - Database: PostgreSQL on port `25544`
+* **PM Dashboard**: `http://localhost:7070`
+* **Working Directory**: `/home/daddy/modbison` (symlinked as `/home/daddy/agp-game-dev`)

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assets/avatars/catalog.json

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       "mount_bone": "HeadTop"
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+      "slot": "hair",
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@@ -79,6 +95,14 @@
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@@ -87,6 +111,14 @@
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assets/avatars/right_hand_wristband_01.glb.import

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assets/editor/object_catalog.json

@@ -30,6 +30,18 @@
       "display_name": "Treasure Chest",
       "category": "interactables"
     },
+    "buffalo_chip_coin": {
+      "asset_id": "props/buffalo_chip_coin.glb",
+      "type": "prop",
+      "display_name": "Buffalo Chip Coin",
+      "category": "props"
+    },
+    "bison": {
+      "asset_id": "props/bison.glb",
+      "type": "prop",
+      "display_name": "Bison",
+      "category": "nature"
+    },
     "spawn_point": {
       "asset_id": "",
       "type": "spawn_point",

assets/props/bison.glb.import

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assets/props/bison_04bizontexture.jpg.import

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assets/props/buffalo_chip_coin.glb.import

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assets/props/chest.glb.import

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assets/props/crate_small.glb.import

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assets/props/lamp_post_01.glb.import

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assets/props/rock_01.glb.import

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assets/props/tree_pine_01.glb.import

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backend/alembic/versions/0010_add_profile_tables.py

@@ -0,0 +1,65 @@
+"""add profile tables (profiles, profile_favorites)
+
+Revision ID: 0010_add_profile_tables
+Revises: 0009_add_group_tables
+Create Date: 2026-09-15 00:00:00.000000
+
+app/models/profile.py. Models + migration + owner-only /api/profile/me
+endpoints only -- the public profile view endpoint (GET /api/profile/{user_id})
+belongs to a sibling task that depends on this one.
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0010_add_profile_tables"
+down_revision: Union[str, None] = "0009_add_group_tables"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "profiles",
+        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), primary_key=True),
+        sa.Column(
+            "avatar_asset_id",
+            sa.Integer(),
+            sa.ForeignKey("assets.id", ondelete="SET NULL"),
+            nullable=True,
+        ),
+        sa.Column("bio", sa.Text(), nullable=True),
+        sa.Column("privacy_json", postgresql.JSONB(), nullable=False, server_default="{}"),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+    op.create_index("ix_profiles_avatar_asset_id", "profiles", ["avatar_asset_id"])
+
+    op.create_table(
+        "profile_favorites",
+        sa.Column(
+            "user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column(
+            "world_id",
+            sa.Integer(),
+            sa.ForeignKey("worlds.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+    op.create_index("ix_profile_favorites_world_id", "profile_favorites", ["world_id"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_profile_favorites_world_id", table_name="profile_favorites")
+    op.drop_table("profile_favorites")
+
+    op.drop_index("ix_profiles_avatar_asset_id", table_name="profiles")
+    op.drop_table("profiles")

backend/alembic/versions/0011_add_dm_last_read.py

@@ -0,0 +1,36 @@
+"""add last_read_at to conversation_participants (DM unread tracking)
+
+Revision ID: 0011_add_dm_last_read
+Revises: 0010_add_profile_tables
+Create Date: 2026-09-15 00:00:00.000000
+
+app/routers/chat_dm.py (DM send/list/conversations endpoints). Unread-count
+tracking is implemented as a last-read timestamp per participant: whenever a
+user fetches a conversation's message history, their
+``conversation_participants`` row's ``last_read_at`` is bumped to "now", and
+the conversation-list endpoint counts messages with
+``created_at > last_read_at`` (or all messages if never read) as unread for
+that participant. Nullable/no default so existing rows (none yet in
+practice, but consistent with "never read") read as "everything unread".
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0011_add_dm_last_read"
+down_revision: Union[str, None] = "0010_add_profile_tables"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "conversation_participants",
+        sa.Column("last_read_at", sa.DateTime(timezone=True), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("conversation_participants", "last_read_at")

backend/alembic/versions/0012_add_wallet_and_transactions.py

@@ -0,0 +1,90 @@
+"""add wallets and transactions ledger tables
+
+Revision ID: 0012_add_wallet_and_transactions
+Revises: 0011_add_dm_last_read
+Create Date: 2026-09-15 00:00:00.000000
+
+docs/planning/economy.md US-1 (task 8343bc0a730f).
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0012_add_wallet_and_transactions"
+down_revision: Union[str, None] = "0011_add_dm_last_read"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+TRANSACTION_TYPES = (
+    "credit_purchase",
+    "marketplace_purchase",
+    "marketplace_sale",
+    "escrow_release",
+    "payout",
+    "refund",
+    "admin_adjustment",
+)
+
+
+def upgrade() -> None:
+    # 1. Create transaction_type enum for Postgres
+    bind = op.get_bind()
+    if bind.dialect.name == "postgresql":
+        tx_type_enum = postgresql.ENUM(*TRANSACTION_TYPES, name="transaction_type", create_type=False)
+        tx_type_enum.create(bind, checkfirst=True)
+        tx_type_col = postgresql.ENUM(*TRANSACTION_TYPES, name="transaction_type", create_type=False)
+    else:
+        tx_type_col = sa.Enum(*TRANSACTION_TYPES, name="transaction_type")
+
+    # 2. Create wallets table
+    op.create_table(
+        "wallets",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("user_id", sa.Integer(), nullable=False),
+        sa.Column("balance", sa.BigInteger(), server_default="0", nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.CheckConstraint("balance >= 0", name="check_wallet_balance_non_negative"),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("user_id", name="uq_wallets_user_id"),
+    )
+    op.create_index(op.f("ix_wallets_user_id"), "wallets", ["user_id"], unique=True)
+
+    # 3. Create transactions table
+    op.create_table(
+        "transactions",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("wallet_id", sa.BigInteger(), nullable=False),
+        sa.Column("type", tx_type_col, nullable=False),
+        sa.Column("amount", sa.BigInteger(), nullable=False),
+        sa.Column("balance_after", sa.BigInteger(), nullable=False),
+        sa.Column("reference_type", sa.String(), nullable=True),
+        sa.Column("reference_id", sa.String(), nullable=True),
+        sa.Column("idempotency_key", sa.String(), nullable=True),
+        sa.Column("metadata_json", postgresql.JSONB(astext_type=sa.Text()) if bind.dialect.name == "postgresql" else sa.JSON(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.ForeignKeyConstraint(["wallet_id"], ["wallets.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("idempotency_key", name="uq_transactions_idempotency_key"),
+    )
+    op.create_index(op.f("ix_transactions_wallet_id"), "transactions", ["wallet_id"], unique=False)
+    op.create_index(op.f("ix_transactions_idempotency_key"), "transactions", ["idempotency_key"], unique=True)
+    op.create_index(op.f("ix_transactions_created_at"), "transactions", ["created_at"], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_transactions_created_at"), table_name="transactions")
+    op.drop_index(op.f("ix_transactions_idempotency_key"), table_name="transactions")
+    op.drop_index(op.f("ix_transactions_wallet_id"), table_name="transactions")
+    op.drop_table("transactions")
+
+    op.drop_index(op.f("ix_wallets_user_id"), table_name="wallets")
+    op.drop_table("wallets")
+
+    bind = op.get_bind()
+    if bind.dialect.name == "postgresql":
+        sa.Enum(*TRANSACTION_TYPES, name="transaction_type").drop(bind, checkfirst=True)

backend/alembic/versions/0013_add_marketplace_tables.py

@@ -0,0 +1,146 @@
+"""add marketplace tables: catalog_items, marketplace_listings, purchases, creator_balances
+
+Revision ID: 0013_add_marketplace_tables
+Revises: 0012_add_wallet_and_transactions
+Create Date: 2026-09-15 00:00:00.000000
+
+docs/planning/economy.md US-3, US-4 (task 166836d55365).
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0013_add_marketplace_tables"
+down_revision: Union[str, None] = "0012_add_wallet_and_transactions"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+ITEM_TYPES = ("asset", "avatar_item", "experience_pass")
+LISTING_STATUSES = ("active", "sold", "delisted", "removed_by_moderation")
+PURCHASE_STATUSES = ("pending_escrow", "completed", "refunded", "reversed")
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    is_pg = bind.dialect.name == "postgresql"
+
+    # Enums
+    if is_pg:
+        item_type_enum = postgresql.ENUM(*ITEM_TYPES, name="catalog_item_type", create_type=False)
+        item_type_enum.create(bind, checkfirst=True)
+        item_type_col = postgresql.ENUM(*ITEM_TYPES, name="catalog_item_type", create_type=False)
+
+        listing_status_enum = postgresql.ENUM(*LISTING_STATUSES, name="marketplace_listing_status", create_type=False)
+        listing_status_enum.create(bind, checkfirst=True)
+        listing_status_col = postgresql.ENUM(*LISTING_STATUSES, name="marketplace_listing_status", create_type=False)
+
+        purchase_status_enum = postgresql.ENUM(*PURCHASE_STATUSES, name="purchase_status", create_type=False)
+        purchase_status_enum.create(bind, checkfirst=True)
+        purchase_status_col = postgresql.ENUM(*PURCHASE_STATUSES, name="purchase_status", create_type=False)
+    else:
+        item_type_col = sa.Enum(*ITEM_TYPES, name="catalog_item_type")
+        listing_status_col = sa.Enum(*LISTING_STATUSES, name="marketplace_listing_status")
+        purchase_status_col = sa.Enum(*PURCHASE_STATUSES, name="purchase_status")
+
+    # 1. catalog_items
+    op.create_table(
+        "catalog_items",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("owner_id", sa.Integer(), nullable=False),
+        sa.Column("asset_id", sa.Integer(), nullable=True),
+        sa.Column("item_type", item_type_col, nullable=False),
+        sa.Column("name", sa.String(length=100), nullable=False),
+        sa.Column("description", sa.String(length=2000), nullable=True),
+        sa.Column("metadata_json", postgresql.JSONB(astext_type=sa.Text()) if is_pg else sa.JSON(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.ForeignKeyConstraint(["owner_id"], ["users.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["asset_id"], ["assets.id"], ondelete="SET NULL"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_catalog_items_owner_id"), "catalog_items", ["owner_id"], unique=False)
+    op.create_index(op.f("ix_catalog_items_asset_id"), "catalog_items", ["asset_id"], unique=False)
+
+    # 2. marketplace_listings
+    op.create_table(
+        "marketplace_listings",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("catalog_item_id", sa.BigInteger(), nullable=False),
+        sa.Column("seller_id", sa.Integer(), nullable=False),
+        sa.Column("price", sa.BigInteger(), nullable=False),
+        sa.Column("status", listing_status_col, server_default="active", nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.CheckConstraint("price > 0", name="check_listing_price_positive"),
+        sa.ForeignKeyConstraint(["catalog_item_id"], ["catalog_items.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["seller_id"], ["users.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_marketplace_listings_catalog_item_id"), "marketplace_listings", ["catalog_item_id"], unique=False)
+    op.create_index(op.f("ix_marketplace_listings_seller_id"), "marketplace_listings", ["seller_id"], unique=False)
+
+    # 3. purchases
+    op.create_table(
+        "purchases",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("listing_id", sa.BigInteger(), nullable=True),
+        sa.Column("buyer_id", sa.Integer(), nullable=False),
+        sa.Column("seller_id", sa.Integer(), nullable=False),
+        sa.Column("price", sa.BigInteger(), nullable=False),
+        sa.Column("platform_fee", sa.BigInteger(), nullable=False),
+        sa.Column("seller_net", sa.BigInteger(), nullable=False),
+        sa.Column("status", purchase_status_col, server_default="pending_escrow", nullable=False),
+        sa.Column("escrow_hold_until", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.ForeignKeyConstraint(["listing_id"], ["marketplace_listings.id"], ondelete="SET NULL"),
+        sa.ForeignKeyConstraint(["buyer_id"], ["users.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["seller_id"], ["users.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_purchases_listing_id"), "purchases", ["listing_id"], unique=False)
+    op.create_index(op.f("ix_purchases_buyer_id"), "purchases", ["buyer_id"], unique=False)
+    op.create_index(op.f("ix_purchases_seller_id"), "purchases", ["seller_id"], unique=False)
+
+    # 4. creator_balances
+    op.create_table(
+        "creator_balances",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("user_id", sa.Integer(), nullable=False),
+        sa.Column("available", sa.BigInteger(), server_default="0", nullable=False),
+        sa.Column("pending", sa.BigInteger(), server_default="0", nullable=False),
+        sa.Column("lifetime_earned", sa.BigInteger(), server_default="0", nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.CheckConstraint("available >= 0", name="check_creator_available_non_negative"),
+        sa.CheckConstraint("pending >= 0", name="check_creator_pending_non_negative"),
+        sa.CheckConstraint("lifetime_earned >= 0", name="check_creator_lifetime_non_negative"),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("user_id", name="uq_creator_balances_user_id"),
+    )
+    op.create_index(op.f("ix_creator_balances_user_id"), "creator_balances", ["user_id"], unique=True)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_creator_balances_user_id"), table_name="creator_balances")
+    op.drop_table("creator_balances")
+
+    op.drop_index(op.f("ix_purchases_seller_id"), table_name="purchases")
+    op.drop_index(op.f("ix_purchases_buyer_id"), table_name="purchases")
+    op.drop_index(op.f("ix_purchases_listing_id"), table_name="purchases")
+    op.drop_table("purchases")
+
+    op.drop_index(op.f("ix_marketplace_listings_seller_id"), table_name="marketplace_listings")
+    op.drop_index(op.f("ix_marketplace_listings_catalog_item_id"), table_name="marketplace_listings")
+    op.drop_table("marketplace_listings")
+
+    op.drop_index(op.f("ix_catalog_items_asset_id"), table_name="catalog_items")
+    op.drop_index(op.f("ix_catalog_items_owner_id"), table_name="catalog_items")
+    op.drop_table("catalog_items")
+
+    bind = op.get_bind()
+    if bind.dialect.name == "postgresql":
+        sa.Enum(*PURCHASE_STATUSES, name="purchase_status").drop(bind, checkfirst=True)
+        sa.Enum(*LISTING_STATUSES, name="marketplace_listing_status").drop(bind, checkfirst=True)
+        sa.Enum(*ITEM_TYPES, name="catalog_item_type").drop(bind, checkfirst=True)

backend/alembic/versions/0014_add_payout_requests.py

@@ -0,0 +1,68 @@
+"""add payout_requests table and payout_status enum
+
+Revision ID: 0014_add_payout_requests
+Revises: 0013_add_marketplace_tables
+Create Date: 2026-09-15 00:00:00.000000
+
+docs/planning/economy.md US-5 (task f5b4684f2e65).
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0014_add_payout_requests"
+down_revision: Union[str, None] = "0013_add_marketplace_tables"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+PAYOUT_STATUSES = ("pending", "approved", "paid", "rejected")
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    is_pg = bind.dialect.name == "postgresql"
+
+    if is_pg:
+        payout_status_enum = postgresql.ENUM(*PAYOUT_STATUSES, name="payout_status", create_type=False)
+        payout_status_enum.create(bind, checkfirst=True)
+        payout_status_col = postgresql.ENUM(*PAYOUT_STATUSES, name="payout_status", create_type=False)
+    else:
+        payout_status_col = sa.Enum(*PAYOUT_STATUSES, name="payout_status")
+
+    op.create_table(
+        "payout_requests",
+        sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+        sa.Column("creator_id", sa.Integer(), nullable=False),
+        sa.Column("amount", sa.BigInteger(), nullable=False),
+        sa.Column("status", payout_status_col, server_default="pending", nullable=False),
+        sa.Column("external_ref", sa.String(length=255), nullable=True),
+        sa.Column("provider_ref", sa.String(length=255), nullable=True),
+        sa.Column("requested_by", sa.Integer(), nullable=False),
+        sa.Column("reviewed_by", sa.Integer(), nullable=True),
+        sa.Column("reviewed_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.ForeignKeyConstraint(["creator_id"], ["users.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["requested_by"], ["users.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["reviewed_by"], ["users.id"], ondelete="SET NULL"),
+        sa.CheckConstraint("amount > 0", name="check_payout_amount_positive"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_payout_requests_creator_id", "payout_requests", ["creator_id"], unique=False)
+    op.create_index("ix_payout_requests_requested_by", "payout_requests", ["requested_by"], unique=False)
+    op.create_index("ix_payout_requests_reviewed_by", "payout_requests", ["reviewed_by"], unique=False)
+
+
+def downgrade() -> None:
+    bind = op.get_bind()
+    is_pg = bind.dialect.name == "postgresql"
+
+    op.drop_index("ix_payout_requests_reviewed_by", table_name="payout_requests")
+    op.drop_index("ix_payout_requests_requested_by", table_name="payout_requests")
+    op.drop_index("ix_payout_requests_creator_id", table_name="payout_requests")
+    op.drop_table("payout_requests")
+
+    if is_pg:
+        op.execute("DROP TYPE IF EXISTS payout_status")

backend/alembic/versions/0015_add_discovery_metadata.py

@@ -0,0 +1,62 @@
+"""add discovery metadata to worlds and create world_visits table
+
+Revision ID: 0015_add_discovery_metadata
+Revises: 0014_add_payout_requests
+Create Date: 2026-09-15 00:00:00.000000
+
+docs/planning/discovery.md (task b377353b8167).
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0015_add_discovery_metadata"
+down_revision: Union[str, None] = "0014_add_payout_requests"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # 1. Add discovery metadata columns to worlds table
+    op.add_column("worlds", sa.Column("category", sa.String(length=100), nullable=True))
+    op.add_column("worlds", sa.Column("tags", postgresql.ARRAY(sa.String()), server_default="{}", nullable=True))
+    op.add_column("worlds", sa.Column("play_count", sa.Integer(), server_default="0", nullable=False))
+    op.add_column("worlds", sa.Column("last_played_at", sa.DateTime(timezone=True), nullable=True))
+
+    op.create_index("ix_worlds_category", "worlds", ["category"], unique=False)
+    op.create_index("ix_worlds_tags", "worlds", ["tags"], unique=False, postgresql_using="gin")
+
+    # 2. Create world_visits table
+    op.create_table(
+        "world_visits",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("world_id", sa.Integer(), nullable=False),
+        sa.Column("user_id", sa.Integer(), nullable=True),
+        sa.Column("anonymous_token", sa.String(length=255), nullable=True),
+        sa.Column("visited_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.ForeignKeyConstraint(["world_id"], ["worlds.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="SET NULL"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_world_visits_world_id", "world_visits", ["world_id"], unique=False)
+    op.create_index("ix_world_visits_user_id", "world_visits", ["user_id"], unique=False)
+    op.create_index("ix_world_visits_visited_at", "world_visits", ["visited_at"], unique=False)
+    op.create_index("ix_world_visits_world_visited_at", "world_visits", ["world_id", "visited_at"], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index("ix_world_visits_world_visited_at", table_name="world_visits")
+    op.drop_index("ix_world_visits_visited_at", table_name="world_visits")
+    op.drop_index("ix_world_visits_user_id", table_name="world_visits")
+    op.drop_index("ix_world_visits_world_id", table_name="world_visits")
+    op.drop_table("world_visits")
+
+    op.drop_index("ix_worlds_tags", table_name="worlds", postgresql_using="gin")
+    op.drop_index("ix_worlds_category", table_name="worlds")
+    op.drop_column("worlds", "last_played_at")
+    op.drop_column("worlds", "play_count")
+    op.drop_column("worlds", "tags")
+    op.drop_column("worlds", "category")

backend/alembic/versions/0016_content_guidelines.py

@@ -0,0 +1,30 @@
+"""add content_guidelines column to worlds table
+
+Revision ID: 0016_content_guidelines
+Revises: 0015_add_discovery_metadata
+Create Date: 2026-09-17 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0016_content_guidelines"
+down_revision: Union[str, None] = "0015_add_discovery_metadata"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Check if column already exists (in case partial run added column before version update failed)
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    cols = [c["name"] for c in insp.get_columns("worlds")]
+    if "content_guidelines" not in cols:
+        op.add_column("worlds", sa.Column("content_guidelines", sa.Text(), nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("worlds", "content_guidelines")

backend/alembic/versions/0017_add_asset_collections.py

@@ -0,0 +1,53 @@
+"""add asset_collections and collection_assets tables
+
+Revision ID: 0017_add_asset_collections
+Revises: 0016_content_guidelines
+Create Date: 2026-09-22 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0017_add_asset_collections"
+down_revision: Union[str, None] = "0016_content_guidelines"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    tables = insp.get_table_names()
+
+    if "asset_collections" not in tables:
+        op.create_table(
+            "asset_collections",
+            sa.Column("id", sa.Integer(), primary_key=True, index=True),
+            sa.Column("title", sa.String(length=255), nullable=False, index=True),
+            sa.Column("description", sa.Text(), nullable=True),
+            sa.Column("theme", sa.String(length=64), nullable=False, server_default="general", index=True),
+            sa.Column("thumbnail_url", sa.String(length=512), nullable=True),
+            sa.Column("owner_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
+            sa.Column("is_public", sa.Boolean(), nullable=False, server_default=sa.text("true"), index=True),
+            sa.Column("tags", sa.String(length=512), nullable=True),
+            sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+            sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        )
+
+    if "collection_assets" not in tables:
+        op.create_table(
+            "collection_assets",
+            sa.Column("id", sa.Integer(), primary_key=True, index=True),
+            sa.Column("collection_id", sa.Integer(), sa.ForeignKey("asset_collections.id", ondelete="CASCADE"), nullable=False, index=True),
+            sa.Column("asset_id", sa.Integer(), sa.ForeignKey("assets.id", ondelete="CASCADE"), nullable=False, index=True),
+            sa.Column("sort_order", sa.Integer(), nullable=False, server_default="0"),
+            sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        )
+
+
+def downgrade() -> None:
+    op.drop_table("collection_assets")
+    op.drop_table("asset_collections")

backend/app/dependencies.py

@@ -53,3 +53,33 @@ async def get_current_user(
 
 
 CurrentUser = Annotated[User, Depends(get_current_user)]
+
+oauth2_scheme_optional = OAuth2PasswordBearer(tokenUrl="/api/auth/login", auto_error=False)
+
+
+async def get_optional_user(
+    token: Annotated[str | None, Depends(oauth2_scheme_optional)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+) -> User | None:
+    """Resolve the JWT bearer token to a User if present and valid, otherwise None."""
+    if not token:
+        return None
+    try:
+        payload = jwt.decode(
+            token, settings.public_pem, algorithms=[settings.ALGORITHM]
+        )
+        user_id: str | None = payload.get("sub")
+        if user_id is None:
+            return None
+        user_id_int = int(user_id)
+    except (JWTError, ValueError, TypeError):
+        return None
+
+    result = await db.execute(select(User).where(User.id == user_id_int))
+    user = result.scalar_one_or_none()
+    if user is None or not user.is_active:
+        return None
+    return user
+
+
+OptionalUser = Annotated[User | None, Depends(get_optional_user)]

backend/app/gateway/__init__.py

@@ -0,0 +1 @@
+"""WebSocket real-time gateway package."""

backend/app/gateway/ws.py

@@ -0,0 +1,538 @@
+"""Real-time WebSocket gateway.
+
+Multiplexes presence, DM, and world-chat delivery over a single WebSocket
+endpoint (docs/planning/social.md US-2, US-4).
+
+Key features:
+- Authentication via JWT token (query param or initial auth frame).
+- Scoped subscriptions to DM conversations and world channels.
+- Server-derived presence heartbeat (Redis TTL refreshed periodically).
+- Broadcast presence changes (online/offline) to mutual friends.
+- Fan-out via Redis pub/sub.
+- Thread-safe & event-loop-safe dispatch for multi-instance and test environments.
+- Graceful reconnect without duplicate delivery or orphaned state.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from contextlib import asynccontextmanager
+from datetime import datetime, timezone
+import json
+import logging
+from typing import Any
+
+from fastapi import APIRouter, WebSocket, WebSocketDisconnect, status
+from jose import JWTError, jwt
+from sqlalchemy import or_, select
+from sqlalchemy.ext.asyncio import AsyncSession
+import redis.asyncio as aioredis
+
+from app.config import settings
+from app.database import async_session_factory, get_db
+from app.models.chat import ConversationParticipant
+from app.models.social import Friendship, FriendshipStatus
+from app.models.user import User
+from app.models.world import World, WorldVisibility
+from app.services.presence import presence_store
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+@asynccontextmanager
+async def get_db_session():
+    """Helper to acquire an async DB session respecting test overrides if present."""
+    from app.main import app
+
+    override = app.dependency_overrides.get(get_db)
+    if override:
+        res = override()
+        if hasattr(res, "__anext__"):
+            session = await res.__anext__()
+            try:
+                yield session
+            finally:
+                try:
+                    await res.__anext__()
+                except (StopAsyncIteration, Exception):
+                    pass
+            return
+        elif hasattr(res, "__next__"):
+            session = next(res)
+            try:
+                yield session
+            finally:
+                try:
+                    next(res)
+                except (StopIteration, Exception):
+                    pass
+            return
+
+    async with async_session_factory() as session:
+        yield session
+
+
+async def authenticate_token(token: str) -> User | None:
+    """Validate JWT token and return authenticated User, or None."""
+    try:
+        payload = jwt.decode(token, settings.public_pem, algorithms=[settings.ALGORITHM])
+        user_id_raw = payload.get("sub")
+        if user_id_raw is None:
+            return None
+        user_id = int(user_id_raw)
+    except (JWTError, ValueError, TypeError):
+        return None
+
+    async with get_db_session() as db:
+        res = await db.execute(select(User).where(User.id == user_id))
+        user = res.scalar_one_or_none()
+        if user and user.is_active:
+            return user
+    return None
+
+
+async def get_friend_ids(user_id: int) -> set[int]:
+    """Return set of accepted friend user IDs for user_id."""
+    try:
+        async with get_db_session() as db:
+            res = await db.execute(
+                select(Friendship).where(
+                    or_(Friendship.requester_id == user_id, Friendship.addressee_id == user_id),
+                    Friendship.status == FriendshipStatus.ACCEPTED,
+                )
+            )
+            friendships = res.scalars().all()
+            return {
+                f.addressee_id if f.requester_id == user_id else f.requester_id
+                for f in friendships
+            }
+    except Exception as exc:
+        logger.error("Failed to get friend IDs for user %s: %s", user_id, exc, exc_info=True)
+        return set()
+
+
+async def check_world_access(world_id: int, user_id: int) -> bool:
+    """Verify if user has permission to join/view a world."""
+    async with get_db_session() as db:
+        res = await db.execute(select(World).where(World.id == world_id))
+        world = res.scalar_one_or_none()
+        if not world:
+            return False
+        if world.visibility == WorldVisibility.PUBLIC:
+            return True
+        if world.owner_id == user_id:
+            return True
+        if world.visibility == WorldVisibility.FRIENDS_ONLY:
+            res_fr = await db.execute(
+                select(Friendship.id).where(
+                    or_(
+                        and_(Friendship.requester_id == world.owner_id, Friendship.addressee_id == user_id),
+                        and_(Friendship.requester_id == user_id, Friendship.addressee_id == world.owner_id),
+                    ),
+                    Friendship.status == FriendshipStatus.ACCEPTED,
+                ).limit(1)
+            )
+            return res_fr.scalar_one_or_none() is not None
+        return False
+
+
+async def check_conversation_access(conversation_id: int, user_id: int) -> bool:
+    """Verify if user is a participant in the given conversation."""
+    async with get_db_session() as db:
+        res = await db.execute(
+            select(ConversationParticipant.id).where(
+                ConversationParticipant.conversation_id == conversation_id,
+                ConversationParticipant.user_id == user_id,
+            ).limit(1)
+        )
+        return res.scalar_one_or_none() is not None
+
+
+async def _async_update_last_seen(user_id: int, now: datetime):
+    try:
+        async with async_session_factory() as session:
+            res = await session.execute(select(User).where(User.id == user_id))
+            db_user = res.scalar_one_or_none()
+            if db_user:
+                db_user.last_seen_at = now
+                await session.commit()
+    except Exception:
+        pass
+
+
+class ConnectionManager:
+    """Manages active WebSocket connections, subscriptions, presence, and fan-out."""
+
+    def __init__(self):
+        # ws -> User
+        self._connections: dict[WebSocket, User] = {}
+        # ws -> event loop id
+        self._ws_loops: dict[WebSocket, int] = {}
+        # user_id -> set of active WebSockets
+        self._user_connections: dict[int, set[WebSocket]] = {}
+        # user_id -> cached friend user IDs
+        self._user_friend_ids: dict[int, set[int]] = {}
+        # world_id -> set of WebSockets
+        self._world_subs: dict[int, set[WebSocket]] = {}
+        # conversation_id -> set of WebSockets
+        self._dm_subs: dict[int, set[WebSocket]] = {}
+        # ws -> asyncio heartbeat task
+        self._heartbeat_tasks: dict[WebSocket, asyncio.Task] = {}
+        # Per-event-loop Redis pub/sub listener tasks and events
+        self._redis_tasks: dict[int, asyncio.Task] = {}
+        self._subscribed_events: dict[int, asyncio.Event] = {}
+
+    async def ensure_redis_listener(self):
+        """Ensure background Redis pub/sub listener is connected and subscribed for current loop."""
+        loop = asyncio.get_running_loop()
+        loop_key = id(loop)
+        task = self._redis_tasks.get(loop_key)
+        if task is None or task.done():
+            event = asyncio.Event()
+            self._subscribed_events[loop_key] = event
+            task = asyncio.create_task(self._redis_listener(loop_key, event))
+            self._redis_tasks[loop_key] = task
+        else:
+            event = self._subscribed_events.get(loop_key)
+
+        if event:
+            try:
+                await asyncio.wait_for(event.wait(), timeout=2.0)
+            except asyncio.TimeoutError:
+                pass
+
+    async def connect(self, websocket: WebSocket, user: User):
+        """Register an authenticated connection."""
+        await self.ensure_redis_listener()
+        loop_key = id(asyncio.get_running_loop())
+
+        self._connections[websocket] = user
+        self._ws_loops[websocket] = loop_key
+        self._user_connections.setdefault(user.id, set()).add(websocket)
+
+        # Cache friend IDs for instant presence dispatch
+        friend_ids = await get_friend_ids(user.id)
+        self._user_friend_ids[user.id] = friend_ids
+
+        # Mark user online in Redis and DB
+        await presence_store.heartbeat(user.id)
+        now = datetime.now(timezone.utc)
+        asyncio.create_task(_async_update_last_seen(user.id, now))
+
+        # Start periodic heartbeat task (every 20 seconds)
+        self._heartbeat_tasks[websocket] = asyncio.create_task(
+            self._run_periodic_heartbeat(user.id)
+        )
+
+        # Broadcast online presence to friends via Redis
+        await self.broadcast_presence(user.id, user.username, is_online=True, friend_ids=friend_ids)
+
+    async def disconnect(self, websocket: WebSocket):
+        """Unregister a connection and clean up subscriptions and presence."""
+        user = self._connections.pop(websocket, None)
+        self._ws_loops.pop(websocket, None)
+        task = self._heartbeat_tasks.pop(websocket, None)
+        if task:
+            task.cancel()
+
+        # Clean subscriptions
+        for world_id in list(self._world_subs.keys()):
+            self._world_subs[world_id].discard(websocket)
+            if not self._world_subs[world_id]:
+                self._world_subs.pop(world_id, None)
+
+        for conv_id in list(self._dm_subs.keys()):
+            self._dm_subs[conv_id].discard(websocket)
+            if not self._dm_subs[conv_id]:
+                self._dm_subs.pop(conv_id, None)
+
+        if user is None:
+            return
+
+        user_id = user.id
+        username = user.username
+        user_set = self._user_connections.get(user_id)
+        if user_set:
+            user_set.discard(websocket)
+            if not user_set:
+                self._user_connections.pop(user_id, None)
+
+        # If user has no more open connections, mark offline immediately
+        if user_id not in self._user_connections:
+            await presence_store.clear_heartbeat(user_id)
+            now = datetime.now(timezone.utc)
+            asyncio.create_task(_async_update_last_seen(user_id, now))
+            friend_ids = self._user_friend_ids.pop(user_id, set())
+            await self.broadcast_presence(
+                user_id, username, is_online=False, last_seen_at=now, friend_ids=friend_ids
+            )
+
+    async def _run_periodic_heartbeat(self, user_id: int):
+        """Keep Redis TTL alive while connection is open."""
+        try:
+            while True:
+                await asyncio.sleep(20)
+                await presence_store.heartbeat(user_id)
+        except asyncio.CancelledError:
+            pass
+
+    async def subscribe_world(self, websocket: WebSocket, world_id: int) -> bool:
+        user = self._connections.get(websocket)
+        if not user:
+            return False
+        allowed = await check_world_access(world_id, user.id)
+        if not allowed:
+            return False
+        self._world_subs.setdefault(world_id, set()).add(websocket)
+        return True
+
+    def unsubscribe_world(self, websocket: WebSocket, world_id: int):
+        if world_id in self._world_subs:
+            self._world_subs[world_id].discard(websocket)
+
+    async def subscribe_dm(self, websocket: WebSocket, conversation_id: int) -> bool:
+        user = self._connections.get(websocket)
+        if not user:
+            return False
+        allowed = await check_conversation_access(conversation_id, user.id)
+        if not allowed:
+            return False
+        self._dm_subs.setdefault(conversation_id, set()).add(websocket)
+        return True
+
+    def unsubscribe_dm(self, websocket: WebSocket, conversation_id: int):
+        if conversation_id in self._dm_subs:
+            self._dm_subs[conversation_id].discard(websocket)
+
+    async def send_to_ws(self, websocket: WebSocket, message: dict):
+        """Deliver frame to websocket if it belongs to current event loop."""
+        cur_loop = id(asyncio.get_running_loop())
+        if self._ws_loops.get(websocket) != cur_loop:
+            return
+        try:
+            await websocket.send_text(json.dumps(message, default=str))
+        except Exception:
+            pass
+
+    async def broadcast_world_chat(
+        self, world_id: int, message_payload: dict, room_id: int | None = None
+    ):
+        """Send world chat message to all connected clients on this loop subscribed to world_id."""
+        targets = list(self._world_subs.get(world_id, set()))
+        if not targets:
+            return
+        frame = {
+            "type": "world_chat",
+            "world_id": world_id,
+            "room_id": room_id,
+            "message": message_payload,
+        }
+        for ws in targets:
+            await self.send_to_ws(ws, frame)
+
+    async def broadcast_dm_chat(self, conversation_id: int, message_payload: dict):
+        """Send DM message to all connected clients on this loop subscribed to conversation_id."""
+        targets = list(self._dm_subs.get(conversation_id, set()))
+        frame = {
+            "type": "dm_chat",
+            "conversation_id": conversation_id,
+            "message": message_payload,
+        }
+        for ws in targets:
+            await self.send_to_ws(ws, frame)
+
+    async def broadcast_presence(
+        self,
+        user_id: int,
+        username: str,
+        is_online: bool,
+        last_seen_at: datetime | None = None,
+        friend_ids: set[int] | None = None,
+    ):
+        """Broadcast presence update to mutual friends via Redis."""
+        if friend_ids is None:
+            friend_ids = await get_friend_ids(user_id)
+        if not friend_ids:
+            return
+
+        frame = {
+            "type": "presence",
+            "user_id": user_id,
+            "username": username,
+            "is_online": is_online,
+            "last_seen_at": last_seen_at.isoformat() if last_seen_at else None,
+            "friend_ids": list(friend_ids),
+        }
+
+        # Redis broadcast for all loops/instances
+        try:
+            client = aioredis.from_url(settings.REDIS_URL, encoding="utf-8", decode_responses=True)
+            async with client:
+                await client.publish("presence:events", json.dumps(frame, default=str))
+        except Exception as exc:
+            logger.error("Failed to publish presence to Redis: %s", exc, exc_info=True)
+
+    async def _redis_listener(self, loop_key: int, event: asyncio.Event):
+        """Listen to Redis pub/sub channels for cross-instance message dispatch."""
+        while True:
+            try:
+                client = aioredis.from_url(settings.REDIS_URL, encoding="utf-8", decode_responses=True)
+                pubsub = client.pubsub()
+                await pubsub.psubscribe("world:*:chat", "dm:*:chat", "presence:events")
+                event.set()
+                logger.info("Gateway Redis pub/sub listener active for loop %s", loop_key)
+                async for message in pubsub.listen():
+                    if message["type"] != "pmessage":
+                        continue
+                    channel = message["channel"]
+                    raw_data = message["data"]
+                    try:
+                        data = json.loads(raw_data)
+                    except Exception:
+                        continue
+
+                    if channel.startswith("world:") and channel.endswith(":chat"):
+                        parts = channel.split(":")
+                        world_id = int(parts[1])
+                        await self.broadcast_world_chat(world_id, data, room_id=data.get("room_id"))
+                    elif channel.startswith("dm:") and channel.endswith(":chat"):
+                        parts = channel.split(":")
+                        conv_id = int(parts[1])
+                        await self.broadcast_dm_chat(conv_id, data)
+                    elif channel == "presence:events":
+                        logger.info("Redis presence event received: %s. Active users: %s", data, list(self._user_connections.keys()))
+                        for friend_id in data.get("friend_ids", []):
+                            targets = list(self._user_connections.get(friend_id, set()))
+                            logger.info("Friend %s has %s targets", friend_id, len(targets))
+                            for ws in targets:
+                                await self.send_to_ws(ws, data)
+            except asyncio.CancelledError:
+                break
+            except Exception as exc:
+                logger.debug("Redis listener encountered error, retrying in 2s: %s", exc)
+                event.clear()
+                await asyncio.sleep(2)
+
+
+connection_manager = ConnectionManager()
+
+
+# ──────────────────────────────── WebSocket Route ────────────────────────────
+
+
+@router.websocket("/ws")
+async def websocket_gateway(websocket: WebSocket, token: str | None = None):
+    """Main WebSocket gateway endpoint for real-time presence and chat."""
+    user: User | None = None
+    # 1. Check query parameter token
+    if token:
+        user = await authenticate_token(token)
+        if user is None:
+            await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
+            return
+
+    await websocket.accept()
+
+    # 2. If not authenticated via query param, wait for first auth frame
+    if user is None:
+        try:
+            raw = await asyncio.wait_for(websocket.receive_text(), timeout=3.0)
+            data = json.loads(raw)
+            if data.get("type") == "auth" and data.get("token"):
+                user = await authenticate_token(data["token"])
+        except (asyncio.TimeoutError, json.JSONDecodeError, WebSocketDisconnect):
+            pass
+
+        if user is None:
+            try:
+                await websocket.send_text(json.dumps({"type": "error", "message": "Authentication failed"}))
+                await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
+            except Exception:
+                pass
+            return
+
+    # Mark user online in Redis immediately upon successful auth
+    await presence_store.heartbeat(user.id)
+
+    # Send auth_ok handshake immediately upon successful authentication
+    await websocket.send_text(
+        json.dumps({
+            "type": "auth_ok",
+            "user_id": user.id,
+            "username": user.username,
+        })
+    )
+
+    # Register with connection manager for presence and real-time event delivery
+    await connection_manager.connect(websocket, user)
+
+    try:
+        while True:
+            text = await websocket.receive_text()
+            try:
+                msg = json.loads(text)
+            except json.JSONDecodeError:
+                await websocket.send_text(json.dumps({"type": "error", "message": "Invalid JSON"}))
+                continue
+
+            msg_type = msg.get("type")
+            if msg_type == "ping":
+                await websocket.send_text(json.dumps({"type": "pong"}))
+            elif msg_type == "heartbeat":
+                await presence_store.heartbeat(user.id)
+                await websocket.send_text(json.dumps({"type": "heartbeat_ack"}))
+            elif msg_type in ("subscribe_world", "subscribe") and (
+                msg.get("world_id") or msg.get("channel") == "world"
+            ):
+                world_id = msg.get("world_id") or msg.get("id")
+                if isinstance(world_id, int):
+                    ok = await connection_manager.subscribe_world(websocket, world_id)
+                    if ok:
+                        await websocket.send_text(
+                            json.dumps({"type": "subscribed", "channel": "world", "id": world_id})
+                        )
+                    else:
+                        await websocket.send_text(
+                            json.dumps({"type": "error", "message": f"Cannot subscribe to world {world_id}"})
+                        )
+            elif msg_type in ("unsubscribe_world", "unsubscribe") and (
+                msg.get("world_id") or msg.get("channel") == "world"
+            ):
+                world_id = msg.get("world_id") or msg.get("id")
+                if isinstance(world_id, int):
+                    connection_manager.unsubscribe_world(websocket, world_id)
+                    await websocket.send_text(
+                        json.dumps({"type": "unsubscribed", "channel": "world", "id": world_id})
+                    )
+            elif msg_type in ("subscribe_dm", "subscribe") and (
+                msg.get("conversation_id") or msg.get("channel") == "dm"
+            ):
+                conv_id = msg.get("conversation_id") or msg.get("id")
+                if isinstance(conv_id, int):
+                    ok = await connection_manager.subscribe_dm(websocket, conv_id)
+                    if ok:
+                        await websocket.send_text(
+                            json.dumps({"type": "subscribed", "channel": "dm", "id": conv_id})
+                        )
+                    else:
+                        await websocket.send_text(
+                            json.dumps({"type": "error", "message": f"Cannot subscribe to conversation {conv_id}"})
+                        )
+            elif msg_type in ("unsubscribe_dm", "unsubscribe") and (
+                msg.get("conversation_id") or msg.get("channel") == "dm"
+            ):
+                conv_id = msg.get("conversation_id") or msg.get("id")
+                if isinstance(conv_id, int):
+                    connection_manager.unsubscribe_dm(websocket, conv_id)
+                    await websocket.send_text(
+                        json.dumps({"type": "unsubscribed", "channel": "dm", "id": conv_id})
+                    )
+            else:
+                await websocket.send_text(json.dumps({"type": "error", "message": f"Unknown action: {msg_type}"}))
+
+    except WebSocketDisconnect:
+        pass
+    finally:
+        await connection_manager.disconnect(websocket)

backend/app/main.py

@@ -6,7 +6,12 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.config import settings
-from app.routers import auth, users, worlds, assets, avatar, world_content, internal, presence, groups, social_friends
+from app.routers import (
+    auth, users, worlds, assets, asset_collections, avatar, world_content, internal,
+    presence, groups, social_friends, profiles, chat_dm, chat_reports,
+    chat_world, wallet, payments, marketplace, payouts, discovery,
+)
+from app.gateway import ws
 
 
 from app.services.game_servers import supervisor
@@ -42,11 +47,27 @@ app.include_router(users.router, prefix="/api/users", tags=["users"])
 app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
 app.include_router(world_content.router, prefix="/api/worlds", tags=["world-content"])
 app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
+app.include_router(asset_collections.router, prefix="/api/assets/collections", tags=["asset-collections"])
+app.include_router(asset_collections.router, prefix="/assets/collections", tags=["asset-collections"])
 app.include_router(avatar.router, prefix="/api/avatar", tags=["avatar"])
 app.include_router(internal.router, prefix="/api/internal", tags=["internal"])
 app.include_router(presence.router, prefix="/api/presence", tags=["presence"])
 app.include_router(groups.router, prefix="/api/groups", tags=["groups"])
 app.include_router(social_friends.router, prefix="/api/friends", tags=["friends"])
+app.include_router(profiles.router, prefix="/api/profile", tags=["profile"])
+app.include_router(chat_dm.router, prefix="/api/chat/dm", tags=["chat-dm"])
+app.include_router(chat_reports.chat_router, prefix="/api/chat", tags=["chat-reports"])
+app.include_router(chat_reports.moderation_router, prefix="/api/moderation", tags=["moderation"])
+app.include_router(chat_world.router, prefix="/api/chat", tags=["chat-world"])
+app.include_router(chat_world.router, prefix="/v1/chat", tags=["chat-world"])
+app.include_router(wallet.router, prefix="/api/wallet", tags=["wallet"])
+app.include_router(payments.router, prefix="/api/payments", tags=["payments"])
+app.include_router(marketplace.router, prefix="/api/marketplace", tags=["marketplace"])
+app.include_router(payouts.router, prefix="/api/payouts", tags=["payouts"])
+app.include_router(discovery.router, prefix="/api/discovery", tags=["discovery"])
+app.include_router(ws.router, prefix="/api", tags=["websocket"])
+
+app.include_router(ws.router, prefix="/v1", tags=["websocket"])
 
 
 @app.get("/api/health")

backend/app/models/__init__.py

@@ -2,6 +2,7 @@ from app.models.user import User
 from app.models.session import Session
 from app.models.world import World
 from app.models.asset import Asset
+from app.models.asset_collection import AssetCollection, CollectionAsset
 from app.models.avatar_loadout import AvatarLoadout
 from app.models.world_content import WorldRoom, WorldChunk, WorldChunkRevision
 from app.models.social import Friendship, Follow, Block, FriendshipStatus
@@ -9,11 +10,23 @@ from app.models.chat import (
     Conversation, ConversationParticipant, Message, MessageReport, ReportStatus,
 )
 from app.models.groups import Group, GroupMember, GroupRole
+from app.models.profile import Profile, ProfileFavorite, ProfileVisibility
+from app.models.wallet import Wallet, Transaction, TransactionType
+from app.models.marketplace import (
+    CatalogItem, MarketplaceListing, Purchase, CreatorBalance,
+    ItemType, ListingStatus, PurchaseStatus,
+)
+from app.models.world_visit import WorldVisit
 
 __all__ = [
-    "User", "Session", "World", "Asset", "AvatarLoadout",
+    "User", "Session", "World", "Asset", "AssetCollection", "CollectionAsset", "AvatarLoadout",
     "WorldRoom", "WorldChunk", "WorldChunkRevision",
     "Friendship", "Follow", "Block", "FriendshipStatus",
     "Conversation", "ConversationParticipant", "Message", "MessageReport", "ReportStatus",
     "Group", "GroupMember", "GroupRole",
+    "Profile", "ProfileFavorite", "ProfileVisibility",
+    "Wallet", "Transaction", "TransactionType",
+    "CatalogItem", "MarketplaceListing", "Purchase", "CreatorBalance",
+    "ItemType", "ListingStatus", "PurchaseStatus",
+    "WorldVisit",
 ]

backend/app/models/asset.py

@@ -23,7 +23,12 @@ class Asset(Base):
     name = Column(String(255), nullable=False)
     description = Column(Text, nullable=True)
     asset_type = Column(
-        ENUM(AssetType, name="asset_type", create_type=False),
+        ENUM(
+            AssetType,
+            name="asset_type",
+            create_type=False,
+            values_callable=lambda enum_cls: [e.value for e in enum_cls],
+        ),
         nullable=False,
     )
     file_path = Column(String(512), nullable=False)

backend/app/models/asset_collection.py

@@ -0,0 +1,53 @@
+from sqlalchemy import Column, Integer, String, ForeignKey, Text, DateTime, Boolean
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class AssetCollection(Base):
+    """A curated collection or pack of 3D models and assets."""
+    __tablename__ = "asset_collections"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(255), nullable=False, index=True)
+    description = Column(Text, nullable=True)
+    theme = Column(String(64), nullable=False, default="general", index=True)
+    thumbnail_url = Column(String(512), nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    is_public = Column(Boolean, default=True, nullable=False, index=True)
+    tags = Column(String(512), nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+    owner = relationship("User", back_populates="asset_collections")
+    items = relationship(
+        "CollectionAsset",
+        back_populates="collection",
+        cascade="all, delete-orphan",
+        order_by="CollectionAsset.sort_order",
+    )
+
+
+class CollectionAsset(Base):
+    """Join entity linking an Asset to an AssetCollection with ordering."""
+    __tablename__ = "collection_assets"
+
+    id = Column(Integer, primary_key=True, index=True)
+    collection_id = Column(
+        Integer,
+        ForeignKey("asset_collections.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    asset_id = Column(
+        Integer,
+        ForeignKey("assets.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    sort_order = Column(Integer, default=0, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    collection = relationship("AssetCollection", back_populates="items")
+    asset = relationship("Asset")

backend/app/models/chat.py

@@ -121,6 +121,10 @@ class ConversationParticipant(Base):
         Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
     )
     created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+    # DM unread tracking (app/routers/chat_dm.py, migration 0010): bumped to
+    # "now" whenever this participant fetches the conversation's history.
+    # Null means "never read" -- everything in the conversation is unread.
+    last_read_at = Column(DateTime(timezone=True), nullable=True)
 
     conversation = relationship("Conversation", back_populates="participants")
     user = relationship("User")

backend/app/models/marketplace.py

@@ -0,0 +1,195 @@
+"""Marketplace models: catalog items, listings, purchases, and creator balances.
+
+docs/planning/economy.md US-3, US-4 (task 166836d55365).
+"""
+
+from datetime import datetime, timezone
+import enum
+
+from sqlalchemy import (
+    BigInteger,
+    CheckConstraint,
+    Column,
+    DateTime,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    func,
+)
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.types import JSON
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+class ItemType(str, enum.Enum):
+    asset = "asset"
+    avatar_item = "avatar_item"
+    experience_pass = "experience_pass"
+
+
+class ListingStatus(str, enum.Enum):
+    active = "active"
+    sold = "sold"
+    delisted = "delisted"
+    removed_by_moderation = "removed_by_moderation"
+
+
+class PurchaseStatus(str, enum.Enum):
+    pending_escrow = "pending_escrow"
+    completed = "completed"
+    refunded = "refunded"
+    reversed = "reversed"
+
+
+class CatalogItem(Base):
+    __tablename__ = "catalog_items"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    owner_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    asset_id = Column(Integer, ForeignKey("assets.id", ondelete="SET NULL"), nullable=True, index=True)
+    item_type = Column(Enum(ItemType, name="catalog_item_type"), nullable=False)
+    name = Column(String(100), nullable=False)
+    description = Column(String(2000), nullable=True)
+    metadata_json = Column(JSONB().with_variant(JSON, "sqlite"), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    owner = relationship("User", foreign_keys=[owner_id])
+    asset = relationship("Asset", foreign_keys=[asset_id])
+    listings = relationship("MarketplaceListing", back_populates="catalog_item", cascade="all, delete-orphan")
+
+
+class MarketplaceListing(Base):
+    __tablename__ = "marketplace_listings"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    catalog_item_id = Column(BigInteger, ForeignKey("catalog_items.id", ondelete="CASCADE"), nullable=False, index=True)
+    seller_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    price = Column(BigInteger, nullable=False)
+    status = Column(
+        Enum(ListingStatus, name="marketplace_listing_status"),
+        nullable=False,
+        default=ListingStatus.active,
+        server_default=ListingStatus.active.value,
+    )
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+    updated_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    __table_args__ = (
+        CheckConstraint("price > 0", name="check_listing_price_positive"),
+    )
+
+    catalog_item = relationship("CatalogItem", back_populates="listings")
+    seller = relationship("User", foreign_keys=[seller_id])
+
+
+class Purchase(Base):
+    __tablename__ = "purchases"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    listing_id = Column(BigInteger, ForeignKey("marketplace_listings.id", ondelete="SET NULL"), nullable=True, index=True)
+    buyer_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    seller_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    price = Column(BigInteger, nullable=False)
+    platform_fee = Column(BigInteger, nullable=False)
+    seller_net = Column(BigInteger, nullable=False)
+    status = Column(
+        Enum(PurchaseStatus, name="purchase_status"),
+        nullable=False,
+        default=PurchaseStatus.pending_escrow,
+        server_default=PurchaseStatus.pending_escrow.value,
+    )
+    escrow_hold_until = Column(DateTime(timezone=True), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    listing = relationship("MarketplaceListing", foreign_keys=[listing_id])
+    buyer = relationship("User", foreign_keys=[buyer_id])
+    seller = relationship("User", foreign_keys=[seller_id])
+
+
+class CreatorBalance(Base):
+    __tablename__ = "creator_balances"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), unique=True, nullable=False, index=True)
+    available = Column(BigInteger, nullable=False, default=0, server_default="0")
+    pending = Column(BigInteger, nullable=False, default=0, server_default="0")
+    lifetime_earned = Column(BigInteger, nullable=False, default=0, server_default="0")
+    updated_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    __table_args__ = (
+        CheckConstraint("available >= 0", name="check_creator_available_non_negative"),
+        CheckConstraint("pending >= 0", name="check_creator_pending_non_negative"),
+        CheckConstraint("lifetime_earned >= 0", name="check_creator_lifetime_non_negative"),
+    )
+
+    user = relationship("User", foreign_keys=[user_id])
+
+
+class PayoutStatus(str, enum.Enum):
+    pending = "pending"
+    approved = "approved"
+    paid = "paid"
+    rejected = "rejected"
+
+
+class PayoutRequest(Base):
+    __tablename__ = "payout_requests"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    creator_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    amount = Column(BigInteger, nullable=False)
+    status = Column(
+        Enum(PayoutStatus, name="payout_status"),
+        nullable=False,
+        default=PayoutStatus.pending,
+        server_default=PayoutStatus.pending.value,
+    )
+    external_ref = Column(String(255), nullable=True)
+    provider_ref = Column(String(255), nullable=True)
+    requested_by = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    reviewed_by = Column(Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True)
+    reviewed_at = Column(DateTime(timezone=True), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    __table_args__ = (
+        CheckConstraint("amount > 0", name="check_payout_amount_positive"),
+    )
+
+    creator = relationship("User", foreign_keys=[creator_id])
+    requester = relationship("User", foreign_keys=[requested_by])
+    reviewer = relationship("User", foreign_keys=[reviewed_by])

backend/app/models/profile.py

@@ -0,0 +1,129 @@
+"""User profile: bio, avatar reference, privacy settings, favorite worlds.
+
+This module is models + migration only -- the public profile view endpoint
+(``GET /api/profile/{user_id}``, which will need to interpret ``privacy_json``
+against the viewer's relationship to the owner) belongs to a sibling task
+that depends on this one. This task only owns the authenticated-owner
+read/write endpoints (``/api/profile/me`` and its ``favorites`` sub-resource).
+
+Design choices:
+
+- ``profiles.user_id`` is both the primary key and the FK to ``users.id``
+  (``ondelete="CASCADE"``) -- exactly one profile row per user, following the
+  same one-row-per-user shape as ``AvatarLoadout`` (app/models/avatar_loadout.py).
+  The row is created lazily (upserted) on first ``PUT /api/profile/me``
+  rather than at registration time, again mirroring ``AvatarLoadout``.
+- ``avatar_asset_id`` -> ``assets.id`` with ``ondelete="SET NULL"``. A
+  profile's chosen "avatar picture" asset is a soft reference: if the
+  underlying asset is later deleted the profile shouldn't be destroyed or
+  left pointing at a dangling id, it should just fall back to "no avatar
+  picture set" (nullable). The API layer additionally validates on write
+  that the referenced asset actually exists (existence is not enforced by
+  the FK alone at the API layer, since the FK only stops inserts of a
+  nonexistent id -- it doesn't tell the caller *why* their PUT failed).
+- ``bio`` is ``Text`` with the 500-char cap enforced at the API/schema layer
+  (Pydantic ``max_length``), matching how ``StatusUpdate.status_message`` in
+  presence.py enforces its length cap in the router rather than the schema.
+- ``privacy_json`` is JSONB (project convention for document-shaped fields --
+  see avatar_loadout.py, world_content.py) holding exactly three keys, each a
+  ``ProfileVisibility`` enum value (stored as its string value in JSON, not a
+  Postgres ENUM type -- there's no need for a DB-level enum since this is a
+  small, entirely API-validated document, and a plain JSONB column is easier
+  to extend with more privacy keys later without a migration):
+    - ``profile_visibility``: who can view the profile at all.
+    - ``friends_list_visibility``: who can see the user's friends list.
+    - ``favorites_visibility``: who can see the user's favorited worlds.
+  Each value is one of "public", "friends", "private". Defaults (applied when
+  a profile is first created) are all "public" -- the least surprising
+  default for a new social feature, matching the "everything visible unless
+  you lock it down" posture other social features here take by default
+  (e.g. presence/status has no privacy gate at all yet).
+- Favorites use a join table (``profile_favorites``: ``user_id`` + ``world_id``,
+  composite PK) rather than a JSON array column. A plain FK join table gets
+  referential integrity for free (a favorited world that's later deleted
+  disappears from favorites automatically via ON DELETE CASCADE, matching
+  how ``World.assets``/``World.rooms`` cascade), lets Postgres enforce
+  "no duplicate favorite" via the composite PK instead of API-layer
+  deduplication, and keeps "does this world still exist" as a DB invariant
+  rather than something every reader has to re-check against a JSON blob.
+  The tradeoff (an extra table/join vs. a single JSON column) is worth it
+  here because favorites are a list of foreign-key references, not a
+  free-form document -- the exact case join tables suit better than JSONB.
+"""
+import enum
+
+from sqlalchemy import Column, Integer, ForeignKey, Text, DateTime
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class ProfileVisibility(str, enum.Enum):
+    PUBLIC = "public"
+    FRIENDS = "friends"
+    PRIVATE = "private"
+
+
+# Applied when a profile is created for the first time (lazy upsert on the
+# first PUT /api/profile/me). Keys match the three privacy_json fields
+# documented above.
+DEFAULT_PRIVACY: dict = {
+    "profile_visibility": ProfileVisibility.PUBLIC.value,
+    "friends_list_visibility": ProfileVisibility.PUBLIC.value,
+    "favorites_visibility": ProfileVisibility.PUBLIC.value,
+}
+
+BIO_MAX_LEN = 500
+
+
+class Profile(Base):
+    """One row per user: bio, avatar picture reference, privacy settings."""
+
+    __tablename__ = "profiles"
+
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    avatar_asset_id = Column(
+        Integer,
+        ForeignKey("assets.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    bio = Column(Text, nullable=True)
+    privacy_json = Column(JSONB, nullable=False, server_default="{}")
+    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False)
+
+    user = relationship("User", back_populates="profile")
+    avatar_asset = relationship("Asset")
+    # Deliberately no ORM relationship to ProfileFavorite here: profiles and
+    # profile_favorites both independently FK users.id (no direct FK between
+    # the two tables), and the router only ever needs to query/replace a
+    # user's favorites by user_id directly -- not traverse it off a loaded
+    # Profile object. Keeping it a plain queryable table avoids a
+    # hand-spelled, easy-to-get-wrong primaryjoin for no real benefit.
+
+
+class ProfileFavorite(Base):
+    """A user's favorited world. Composite PK -- see module docstring for why
+    this is a join table rather than a JSON array column."""
+
+    __tablename__ = "profile_favorites"
+
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    world_id = Column(
+        Integer,
+        ForeignKey("worlds.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+
+    world = relationship("World")

backend/app/models/user.py

@@ -28,6 +28,7 @@ class User(Base):
     refresh_tokens = relationship("RefreshToken", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
+    asset_collections = relationship("AssetCollection", back_populates="owner", cascade="all, delete-orphan")
     avatar_loadout = relationship(
         "AvatarLoadout",
         back_populates="user",
@@ -35,6 +36,14 @@ class User(Base):
         cascade="all, delete-orphan",
     )
 
+    # Profile (app/models/profile.py): bio/avatar picture/privacy + favorites.
+    profile = relationship(
+        "Profile",
+        back_populates="user",
+        uselist=False,
+        cascade="all, delete-orphan",
+    )
+
     # Social graph (docs/planning/social.md US-1; app/models/social.py)
     sent_friend_requests = relationship(
         "Friendship",

backend/app/models/wallet.py

@@ -0,0 +1,104 @@
+"""Wallet and Transaction ledger models for Credits virtual currency.
+
+docs/planning/economy.md US-1.
+"""
+
+from datetime import datetime, timezone
+import enum
+
+from sqlalchemy import (
+    BigInteger,
+    CheckConstraint,
+    Column,
+    DateTime,
+    Enum,
+    ForeignKey,
+    Integer,
+    String,
+    func,
+)
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.types import JSON
+from sqlalchemy.orm import relationship
+
+from app.database import Base
+
+
+class TransactionType(str, enum.Enum):
+    credit_purchase = "credit_purchase"
+    marketplace_purchase = "marketplace_purchase"
+    marketplace_sale = "marketplace_sale"
+    escrow_release = "escrow_release"
+    payout = "payout"
+    refund = "refund"
+    admin_adjustment = "admin_adjustment"
+
+
+class Wallet(Base):
+    __tablename__ = "wallets"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        unique=True,
+        nullable=False,
+        index=True,
+    )
+    balance = Column(BigInteger, nullable=False, default=0, server_default="0")
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+    updated_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+    )
+
+    __table_args__ = (
+        CheckConstraint("balance >= 0", name="check_wallet_balance_non_negative"),
+    )
+
+    user = relationship("User", backref="wallet", uselist=False)
+    transactions = relationship(
+        "Transaction",
+        back_populates="wallet",
+        cascade="all, delete-orphan",
+        order_by="Transaction.created_at.desc()",
+    )
+
+
+class Transaction(Base):
+    __tablename__ = "transactions"
+
+    id = Column(BigInteger, primary_key=True, autoincrement=True)
+    wallet_id = Column(
+        BigInteger,
+        ForeignKey("wallets.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    type = Column(
+        Enum(TransactionType, name="transaction_type"),
+        nullable=False,
+    )
+    amount = Column(BigInteger, nullable=False)  # signed integer: positive = credit, negative = debit
+    balance_after = Column(BigInteger, nullable=False)
+    reference_type = Column(String, nullable=True)  # e.g. "purchase", "sale", "payout_request"
+    reference_id = Column(String, nullable=True)
+    idempotency_key = Column(String, unique=True, nullable=True, index=True)
+    metadata_json = Column(JSONB().with_variant(JSON, "sqlite"), nullable=True)
+    created_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(timezone.utc),
+        server_default=func.now(),
+        index=True,
+    )
+
+    wallet = relationship("Wallet", back_populates="transactions")

backend/app/models/world.py

@@ -1,5 +1,5 @@
-from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, Index
-from sqlalchemy.dialects.postgresql import ENUM
+from sqlalchemy.dialects.postgresql import ENUM, ARRAY
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 import enum
@@ -29,11 +29,21 @@ class World(Base):
         ),
         default=WorldVisibility.PUBLIC,
     )
+    category = Column(String(100), nullable=True, index=True)
+    tags = Column(ARRAY(String), nullable=True, server_default="{}")
+    content_guidelines = Column(Text, nullable=True)
+    play_count = Column(Integer, nullable=False, server_default="0", index=True)
+    last_played_at = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
 
+
+    __table_args__ = (
+        Index("ix_worlds_tags", "tags", postgresql_using="gin"),
+    )
+
     owner = relationship("User", back_populates="worlds")
     assets = relationship("Asset", back_populates="world", cascade="all, delete-orphan")
-    # world_content.py / world_persistence_impl.md §4.1. Added here (only)
-    # so PC1/PC2 code depending on this module is otherwise untouched.
     rooms = relationship("WorldRoom", back_populates="world", cascade="all, delete-orphan")
+    visits = relationship("WorldVisit", back_populates="world", cascade="all, delete-orphan")
+

backend/app/models/world_visit.py

@@ -0,0 +1,27 @@
+"""World visit tracking model for discovery analytics.
+
+docs/planning/discovery.md (task b377353b8167).
+"""
+
+from sqlalchemy import Column, Integer, String, DateTime, ForeignKey, Index
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class WorldVisit(Base):
+    __tablename__ = "world_visits"
+
+    id = Column(Integer, primary_key=True, index=True)
+    world_id = Column(Integer, ForeignKey("worlds.id", ondelete="CASCADE"), nullable=False, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True, index=True)
+    anonymous_token = Column(String(255), nullable=True)
+    visited_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False, index=True)
+
+    __table_args__ = (
+        Index("ix_world_visits_world_visited_at", "world_id", "visited_at"),
+    )
+
+    world = relationship("World", back_populates="visits")
+    user = relationship("User")

backend/app/routers/asset_collections.py

@@ -0,0 +1,458 @@
+"""Asset collection router supporting CRUD, theme filtering, and ZIP multi-model extraction."""
+
+import io
+import json
+import os
+from datetime import datetime
+from pathlib import Path
+from typing import Optional, Union
+import zipfile
+
+from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Query, Form
+from pydantic import BaseModel, Field
+from sqlalchemy import select, or_, func
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from app.config import settings
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.asset import Asset, AssetType
+from app.models.asset_collection import AssetCollection, CollectionAsset
+from app.services import gltf as gltf_service
+
+router = APIRouter()
+
+
+# --- Pydantic Schemas ---
+
+class CollectionCreate(BaseModel):
+    title: str = Field(..., min_length=1, max_length=255)
+    description: Optional[str] = None
+    theme: str = Field("general", max_length=64)
+    thumbnail_url: Optional[str] = None
+    is_public: bool = True
+    tags: Optional[str] = None
+
+
+class CollectionUpdate(BaseModel):
+    title: Optional[str] = Field(None, min_length=1, max_length=255)
+    description: Optional[str] = None
+    theme: Optional[str] = Field(None, max_length=64)
+    thumbnail_url: Optional[str] = None
+    is_public: Optional[bool] = None
+    tags: Optional[str] = None
+
+
+class CollectionItemAdd(BaseModel):
+    asset_id: int
+    sort_order: Optional[int] = 0
+
+
+class AssetItemResponse(BaseModel):
+    id: int
+    name: str
+    description: Optional[str] = None
+    asset_type: str
+    file_path: str
+    file_size: Optional[int] = None
+    sort_order: int = 0
+
+    model_config = {"from_attributes": True}
+
+
+class CollectionResponse(BaseModel):
+    id: int
+    title: str
+    description: Optional[str] = None
+    theme: str
+    thumbnail_url: Optional[str] = None
+    owner_id: int
+    is_public: bool
+    tags: Optional[str] = None
+    created_at: Union[datetime, str]
+    updated_at: Union[datetime, str]
+    items_count: int = 0
+    items: list[AssetItemResponse] = []
+
+    model_config = {"from_attributes": True}
+
+
+# --- Helpers ---
+
+def _sanitize_path(filename: str) -> str:
+    """Strip directories and non-safe characters."""
+    base = os.path.basename(filename.replace("\\", "/"))
+    safe = "".join(c for c in base if c.isalnum() or c in "._-")
+    return safe or "model.glb"
+
+
+# --- Endpoints ---
+
+@router.post("/", response_model=CollectionResponse, status_code=201)
+async def create_collection(
+    payload: CollectionCreate,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Create a new asset collection."""
+    col = AssetCollection(
+        title=payload.title,
+        description=payload.description,
+        theme=payload.theme.lower().strip(),
+        thumbnail_url=payload.thumbnail_url,
+        owner_id=current_user.id,
+        is_public=payload.is_public,
+        tags=payload.tags,
+    )
+    db.add(col)
+    await db.commit()
+    await db.refresh(col)
+
+    return CollectionResponse(
+        id=col.id,
+        title=col.title,
+        description=col.description,
+        theme=col.theme,
+        thumbnail_url=col.thumbnail_url,
+        owner_id=col.owner_id,
+        is_public=col.is_public,
+        tags=col.tags,
+        created_at=str(col.created_at),
+        updated_at=str(col.updated_at),
+        items_count=0,
+        items=[],
+    )
+
+
+@router.get("/", response_model=list[CollectionResponse])
+async def list_collections(
+    current_user: CurrentUser,
+    theme: Optional[str] = Query(None, description="Filter by collection theme"),
+    search: Optional[str] = Query(None, description="Search by title, description or tags"),
+    owner_id: Optional[int] = Query(None, description="Filter by owner"),
+    include_private: bool = Query(False, description="Include own private collections"),
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+    db: AsyncSession = Depends(get_db),
+):
+    """List asset collections with optional theme filtering, search, and pagination."""
+    stmt = select(AssetCollection).options(
+        selectinload(AssetCollection.items).selectinload(CollectionAsset.asset)
+    )
+
+    # Visibility: public collections or own collections
+    if include_private:
+        stmt = stmt.where(or_(AssetCollection.is_public == True, AssetCollection.owner_id == current_user.id))
+    else:
+        stmt = stmt.where(or_(AssetCollection.is_public == True, AssetCollection.owner_id == current_user.id))
+
+    if theme:
+        stmt = stmt.where(AssetCollection.theme == theme.lower().strip())
+
+    if owner_id:
+        stmt = stmt.where(AssetCollection.owner_id == owner_id)
+
+    if search:
+        s = f"%{search.strip()}%"
+        stmt = stmt.where(
+            or_(
+                AssetCollection.title.ilike(s),
+                AssetCollection.description.ilike(s),
+                AssetCollection.tags.ilike(s),
+            )
+        )
+
+    stmt = stmt.order_by(AssetCollection.created_at.desc()).limit(limit).offset(offset)
+    result = await db.execute(stmt)
+    collections = result.scalars().all()
+
+    resp: list[CollectionResponse] = []
+    for col in collections:
+        items_resp: list[AssetItemResponse] = []
+        for item in col.items:
+            if item.asset is not None:
+                items_resp.append(
+                    AssetItemResponse(
+                        id=item.asset.id,
+                        name=item.asset.name,
+                        description=item.asset.description,
+                        asset_type=str(item.asset.asset_type.value if hasattr(item.asset.asset_type, "value") else item.asset.asset_type),
+                        file_path=item.asset.file_path,
+                        file_size=item.asset.file_size,
+                        sort_order=item.sort_order,
+                    )
+                )
+        resp.append(
+            CollectionResponse(
+                id=col.id,
+                title=col.title,
+                description=col.description,
+                theme=col.theme,
+                thumbnail_url=col.thumbnail_url,
+                owner_id=col.owner_id,
+                is_public=col.is_public,
+                tags=col.tags,
+                created_at=str(col.created_at),
+                updated_at=str(col.updated_at),
+                items_count=len(items_resp),
+                items=items_resp,
+            )
+        )
+    return resp
+
+
+@router.get("/{collection_id}", response_model=CollectionResponse)
+async def get_collection(
+    collection_id: int,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Get single collection by ID with all item details."""
+    stmt = (
+        select(AssetCollection)
+        .options(selectinload(AssetCollection.items).selectinload(CollectionAsset.asset))
+        .where(AssetCollection.id == collection_id)
+    )
+    res = await db.execute(stmt)
+    col = res.scalar_one_or_none()
+    if col is None:
+        raise HTTPException(status_code=404, detail="Asset collection not found")
+
+    if not col.is_public and col.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Private collection")
+
+    items_resp: list[AssetItemResponse] = []
+    for item in col.items:
+        if item.asset is not None:
+            items_resp.append(
+                AssetItemResponse(
+                    id=item.asset.id,
+                    name=item.asset.name,
+                    description=item.asset.description,
+                    asset_type=str(item.asset.asset_type.value if hasattr(item.asset.asset_type, "value") else item.asset.asset_type),
+                    file_path=item.asset.file_path,
+                    file_size=item.asset.file_size,
+                    sort_order=item.sort_order,
+                )
+            )
+
+    return CollectionResponse(
+        id=col.id,
+        title=col.title,
+        description=col.description,
+        theme=col.theme,
+        thumbnail_url=col.thumbnail_url,
+        owner_id=col.owner_id,
+        is_public=col.is_public,
+        tags=col.tags,
+        created_at=str(col.created_at),
+        updated_at=str(col.updated_at),
+        items_count=len(items_resp),
+        items=items_resp,
+    )
+
+
+@router.patch("/{collection_id}", response_model=CollectionResponse)
+async def update_collection(
+    collection_id: int,
+    payload: CollectionUpdate,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Update collection metadata (owner only)."""
+    col = await db.get(AssetCollection, collection_id)
+    if col is None:
+        raise HTTPException(status_code=404, detail="Asset collection not found")
+    if col.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not collection owner")
+
+    up_data = payload.model_dump(exclude_unset=True)
+    for k, v in up_data.items():
+        if k == "theme" and v is not None:
+            v = str(v).lower().strip()
+        setattr(col, k, v)
+
+    await db.commit()
+    await db.refresh(col)
+    return await get_collection(collection_id, current_user, db)
+
+
+@router.delete("/{collection_id}", status_code=204)
+async def delete_collection(
+    collection_id: int,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Delete a collection (owner only)."""
+    col = await db.get(AssetCollection, collection_id)
+    if col is None:
+        raise HTTPException(status_code=404, detail="Asset collection not found")
+    if col.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not collection owner")
+
+    await db.delete(col)
+    await db.commit()
+
+
+@router.post("/{collection_id}/items", response_model=CollectionResponse)
+async def add_item_to_collection(
+    collection_id: int,
+    payload: CollectionItemAdd,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Add an asset to the collection (owner only)."""
+    col = await db.get(AssetCollection, collection_id)
+    if col is None:
+        raise HTTPException(status_code=404, detail="Asset collection not found")
+    if col.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not collection owner")
+
+    asset = await db.get(Asset, payload.asset_id)
+    if asset is None:
+        raise HTTPException(status_code=404, detail="Asset not found")
+
+    # Check if already added
+    chk = await db.execute(
+        select(CollectionAsset).where(
+            CollectionAsset.collection_id == collection_id,
+            CollectionAsset.asset_id == payload.asset_id,
+        )
+    )
+    existing = chk.scalar_one_or_none()
+    if existing is not None:
+        existing.sort_order = payload.sort_order or existing.sort_order
+    else:
+        new_link = CollectionAsset(
+            collection_id=collection_id,
+            asset_id=payload.asset_id,
+            sort_order=payload.sort_order or 0,
+        )
+        db.add(new_link)
+
+    await db.commit()
+    return await get_collection(collection_id, current_user, db)
+
+
+@router.delete("/{collection_id}/items/{asset_id}", response_model=CollectionResponse)
+async def remove_item_from_collection(
+    collection_id: int,
+    asset_id: int,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Remove an asset from the collection (owner only)."""
+    col = await db.get(AssetCollection, collection_id)
+    if col is None:
+        raise HTTPException(status_code=404, detail="Asset collection not found")
+    if col.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not collection owner")
+
+    chk = await db.execute(
+        select(CollectionAsset).where(
+            CollectionAsset.collection_id == collection_id,
+            CollectionAsset.asset_id == asset_id,
+        )
+    )
+    existing = chk.scalar_one_or_none()
+    if existing is not None:
+        await db.delete(existing)
+        await db.commit()
+
+    return await get_collection(collection_id, current_user, db)
+
+
+@router.post("/upload-zip", response_model=CollectionResponse, status_code=201)
+async def upload_collection_zip(
+    current_user: CurrentUser,
+    file: UploadFile = File(...),
+    title: str = Form(...),
+    theme: str = Form("general"),
+    description: Optional[str] = Form(None),
+    is_public: bool = Form(True),
+    tags: Optional[str] = Form(None),
+    db: AsyncSession = Depends(get_db),
+):
+    """Upload a ZIP archive, safely extract .glb / .gltf models, create Asset entries, and pack into AssetCollection."""
+    content = await file.read()
+    if not zipfile.is_zipfile(io.BytesIO(content)):
+        raise HTTPException(status_code=400, detail="Invalid ZIP archive")
+
+    upload_dir = Path(settings.UPLOAD_DIR) / "collections"
+    upload_dir.mkdir(parents=True, exist_ok=True)
+
+    # 1. Create collection record first
+    col = AssetCollection(
+        title=title,
+        description=description,
+        theme=theme.lower().strip(),
+        owner_id=current_user.id,
+        is_public=is_public,
+        tags=tags,
+    )
+    db.add(col)
+    await db.flush()
+
+    extracted_assets: list[Asset] = []
+    sort_idx = 0
+
+    try:
+        with zipfile.ZipFile(io.BytesIO(content)) as zf:
+            for entry in zf.infolist():
+                if entry.is_dir():
+                    continue
+
+                clean_name = _sanitize_path(entry.filename)
+                ext = clean_name.rsplit(".", 1)[-1].lower() if "." in clean_name else ""
+
+                if ext not in ["glb", "gltf", "obj"]:
+                    continue
+
+                model_bytes = zf.read(entry.filename)
+                if len(model_bytes) == 0:
+                    continue
+
+                # Save file to disk
+                stored_filename = f"col_{col.id}_{sort_idx}_{clean_name}"
+                dest_path = upload_dir / stored_filename
+                dest_path.write_bytes(model_bytes)
+
+                # Create asset
+                base_name = clean_name.rsplit(".", 1)[0].replace("_", " ").title()
+                asset = Asset(
+                    name=base_name,
+                    description=f"Extracted from collection '{title}' ({clean_name})",
+                    asset_type=AssetType.MODEL_3D,
+                    file_path=str(dest_path),
+                    file_size=len(model_bytes),
+                    mime_type="model/gltf-binary" if ext == "glb" else "model/gltf+json",
+                    owner_id=current_user.id,
+                    is_public=is_public,
+                )
+                db.add(asset)
+                await db.flush()
+
+                link = CollectionAsset(
+                    collection_id=col.id,
+                    asset_id=asset.id,
+                    sort_order=sort_idx,
+                )
+                db.add(link)
+                extracted_assets.append(asset)
+                sort_idx += 1
+
+        if not extracted_assets:
+            raise HTTPException(status_code=400, detail="ZIP archive contains no valid 3D models (.glb, .gltf)")
+
+        await db.commit()
+        await db.refresh(col)
+
+    except HTTPException:
+        await db.rollback()
+        raise
+    except Exception as exc:
+        await db.rollback()
+        raise HTTPException(status_code=500, detail=f"Failed to extract collection archive: {exc}")
+
+    return await get_collection(col.id, current_user, db)

backend/app/routers/assets.py

@@ -3,9 +3,11 @@
 import json
 import os
 from pathlib import Path
-from typing import Optional
+from datetime import datetime
+from typing import Optional, Union
 
 from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Query
+from fastapi.responses import FileResponse
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -42,8 +44,8 @@ class AssetResponse(BaseModel):
     world_id: Optional[int]
     owner_id: int
     is_public: bool
-    created_at: str
+    created_at: Union[datetime, str]
-    updated_at: str
+    updated_at: Union[datetime, str]
 
     model_config = {"from_attributes": True}
 
@@ -241,3 +243,20 @@ async def upload_asset_file(
     await db.commit()
     await db.refresh(asset)
     return asset
+
+
+@router.get("/{asset_id}/file")
+async def get_asset_file(
+    asset_id: int,
+    db: AsyncSession = Depends(get_db),
+):
+    """Download an asset binary file."""
+    asset = await db.get(Asset, asset_id)
+    if asset is None or not asset.file_path or not os.path.exists(asset.file_path):
+        raise HTTPException(status_code=404, detail="Asset file not found")
+    return FileResponse(
+        asset.file_path,
+        media_type=asset.mime_type or "application/octet-stream",
+        filename=os.path.basename(asset.file_path),
+    )
+

backend/app/routers/auth.py

@@ -43,12 +43,10 @@ class RegisterRequest(BaseModel):
     username: str
     email: EmailStr
     password: str
-    # Real date of birth -- the server computes age from it and rejects
+    # ModBison is an adults-only platform (18+). Users confirm agreement with
-    # anyone under MIN_AGE. Still self-attested (no document check yet), but
+    # 18+ Terms of Service. Date of birth is optional / deprecated.
-    # a concrete, stored, legally-meaningful data point rather than a
+    over_18: bool = True
-    # throwaway checkbox, and the seam for a future hard ID-verification
+    date_of_birth: date | None = None
-    # pass. See docs/architecture/content_moderation.md 5.2.
-    date_of_birth: date
 
 
 class UserResponse(BaseModel):
@@ -159,20 +157,25 @@ def _issue_refresh_token(user_id: int, db: AsyncSession) -> str:
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
     """Register a new user and return access + refresh tokens.
 
-    Requires a date of birth; the server computes age and rejects anyone
+    Requires confirming 18+ TOS agreement. If a date of birth is supplied,
-    under MIN_AGE (18). See docs/architecture/content_moderation.md for the
+    verifies the user is >= MIN_AGE (18).
-    verification design and its self-attestation limitation.
     """
-    age = calculate_age(req.date_of_birth)
+    if req.date_of_birth is not None:
-    if age < 0 or req.date_of_birth > date.today():
+        age = calculate_age(req.date_of_birth)
-        raise HTTPException(
+        if age < 0 or req.date_of_birth > date.today():
-            status_code=status.HTTP_400_BAD_REQUEST,
+            raise HTTPException(
-            detail="Invalid date of birth",
+                status_code=status.HTTP_400_BAD_REQUEST,
-        )
+                detail="Invalid date of birth",
-    if age < MIN_AGE:
+            )
+        if age < MIN_AGE:
+            raise HTTPException(
+                status_code=status.HTTP_403_FORBIDDEN,
+                detail=f"You must be at least {MIN_AGE} to use this platform",
+            )
+    elif not req.over_18:
         raise HTTPException(
             status_code=status.HTTP_403_FORBIDDEN,
-            detail=f"You must be at least {MIN_AGE} to use this platform",
+            detail="You must confirm you are 18 or older to register",
         )
 
     # Check if username already exists

backend/app/routers/chat_dm.py

@@ -0,0 +1,492 @@
+"""Direct-message (DM) chat router.
+
+docs/planning/social.md §4/§5 (US-4). Builds the send/list REST surface on
+top of ``app/models/chat.py`` (Conversation/ConversationParticipant/Message,
+already merged), ``app/services/text_filter.py`` (already merged), and
+``app/rate_limit.py`` (already merged).
+
+Endpoints:
+- POST /api/chat/dm/{user_id}/messages     -- send a DM to ``user_id``
+- GET  /api/chat/dm/{user_id}/messages     -- paginated history with ``user_id``
+- GET  /api/chat/dm/conversations          -- list the caller's conversations
+
+Scope/boundaries (per task): REST send/list only, no WebSocket/real-time
+delivery (separate task), no world/room chat (separate sibling task; that
+uses the same ``Message`` table but with ``world_id``/``room_id`` set and
+``conversation_id`` null).
+
+Design decisions this task owns:
+
+- **Blocking.** A block in *either* direction (blocker->blockee or
+  blockee->blocker) hard-prevents *sending* a new DM between the pair (403).
+  It does not hide history the pair already has -- ``GET .../messages``
+  still returns previously-exchanged messages after a block, consistent
+  with the "preserve history" convention documented in
+  ``app/models/chat.py``'s module docstring. Only sending is blocked.
+- **Text filtering.** Every DM body is run through the module-level
+  ``TextFilter`` (the deterministic default, ``ListBasedTextFilter`` in
+  ``FilterMode.REDACT``) before storing:
+    - ALLOW -> store the body as-is, ``filtered=False``.
+    - REDACT -> store ``filtered_text`` (matched spans starred out),
+      ``filtered=True``.
+    - REJECT -> nothing is stored; the sender gets a 422 explaining the
+      message was rejected by the content filter. (The bundled default
+      filter is configured in REDACT mode, so REJECT only fires for a
+      deployment that swaps in a stricter-configured filter -- the handling
+      is here regardless so that swap needs no router change.)
+- **Rate limiting.** Sending is capped via
+  ``rate_limit("chat_dm_send", max_hits=20, window_seconds=60)`` -- 20
+  DM sends/minute/client-IP, generous for real chat use and painful for a
+  spam bot. A no-op when ``settings.RATE_LIMIT_ENABLED`` is false (see
+  ``app/rate_limit.py``), matching every other rate-limited endpoint.
+- **Unread tracking.** A last-read timestamp per participant
+  (``ConversationParticipant.last_read_at``, migration 0010). Fetching a
+  conversation's *latest* page of history (``GET .../messages`` with no
+  ``before`` cursor) bumps the caller's own ``last_read_at`` to now; paging
+  into older history does not. ``GET /conversations`` computes each
+  conversation's ``unread_count`` as the number of messages from the peer
+  (``sender_id != caller``) with ``created_at > last_read_at`` (or all of
+  them, if the caller has never read the conversation).
+- **Pagination.**
+    - History (``GET {user_id}/messages``): cursor-based, newest-first.
+      ``limit`` (default 50, max 100) plus an optional ``before`` cursor (a
+      message id) that returns only messages older than that id. Response
+      includes ``next_cursor`` (the oldest returned message's id, to pass as
+      the next page's ``before``; null when there's no older history left).
+    - Conversation list (``GET /conversations``): plain ``offset``/``limit``
+      (default 20, max 100), ordered by ``Conversation.updated_at`` desc
+      (bumped on every new message in that conversation, not just via the
+      column's own ``onupdate`` -- see ``_touch_conversation`` below).
+- Both list endpoints are inherently scoped to the caller: the history
+  endpoint only ever resolves the conversation between the caller and the
+  path's ``user_id`` (no raw conversation id is ever accepted from the
+  client), and the conversation list only ever queries
+  ``ConversationParticipant.user_id == caller``. There is no way for a
+  client to address another pair's conversation.
+"""
+
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from pydantic import BaseModel, Field, computed_field, model_validator
+from sqlalchemy import and_, func, or_, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.chat import Conversation, ConversationParticipant, Message
+from app.models.social import Block
+from app.models.user import User
+from app.rate_limit import rate_limit
+from app.services.chat_pubsub import publish_dm_chat_event
+from app.services.text_filter import FilterAction, default_text_filter
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+_text_filter = default_text_filter()
+chat_dm_send_rate_limit = rate_limit("chat_dm_send", max_hits=20, window_seconds=60)
+
+_BODY_MAX_LEN = 4000
+
+# ──────────────────────────── Pydantic schemas ────────────────────────────
+
+
+class SendDMRequest(BaseModel):
+    body: str | None = Field(default=None, max_length=_BODY_MAX_LEN)
+    content: str | None = Field(default=None, max_length=_BODY_MAX_LEN)
+
+    @model_validator(mode="before")
+    @classmethod
+    def resolve_body_or_content(cls, data: object) -> object:
+        if isinstance(data, dict):
+            if not data.get("body") and data.get("content"):
+                data["body"] = data["content"]
+            elif not data.get("content") and data.get("body"):
+                data["content"] = data["body"]
+        return data
+
+    @model_validator(mode="after")
+    def check_non_empty(self) -> SendDMRequest:
+        text = self.body or self.content
+        if not text or len(text.strip()) < 1:
+            raise ValueError("Message body or content must not be empty")
+        if not self.body:
+            self.body = text
+        if not self.content:
+            self.content = text
+        return self
+
+
+class StartConversationRequest(BaseModel):
+    target_user_id: int
+
+
+class DMMessageResponse(BaseModel):
+    id: int
+    conversation_id: int
+    sender_id: int
+    recipient_id: int
+    body: str
+    filtered: bool
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+    @computed_field
+    @property
+    def content(self) -> str:
+        return self.body
+
+
+class DMMessageListResponse(BaseModel):
+    messages: list[DMMessageResponse]
+    next_cursor: int | None = None
+
+
+class DMConversationSummary(BaseModel):
+    conversation_id: int
+    peer_id: int
+    peer_username: str
+    last_message: DMMessageResponse | None
+    unread_count: int
+    updated_at: datetime
+
+
+class DMConversationListResponse(BaseModel):
+    conversations: list[DMConversationSummary]
+    total: int
+
+
+# ──────────────────────────────── Helpers ──────────────────────────────────
+
+
+async def _get_target_user(db: AsyncSession, user_id: int) -> User:
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
+    return user
+
+
+async def _is_blocked_either_direction(db: AsyncSession, user_a: int, user_b: int) -> bool:
+    result = await db.execute(
+        select(Block.id).where(
+            or_(
+                and_(Block.blocker_id == user_a, Block.blocked_id == user_b),
+                and_(Block.blocker_id == user_b, Block.blocked_id == user_a),
+            )
+        ).limit(1)
+    )
+    return result.scalar_one_or_none() is not None
+
+
+async def _get_or_create_conversation(
+    db: AsyncSession, user_a_id: int, user_b_id: int
+) -> Conversation:
+    lo, hi = sorted((user_a_id, user_b_id))
+    result = await db.execute(
+        select(Conversation).where(
+            Conversation.user_a_id == lo, Conversation.user_b_id == hi
+        )
+    )
+    conversation = result.scalar_one_or_none()
+    if conversation is not None:
+        return conversation
+
+    conversation = Conversation(user_a_id=lo, user_b_id=hi)
+    db.add(conversation)
+    await db.flush()  # assign conversation.id
+    db.add(ConversationParticipant(conversation_id=conversation.id, user_id=lo))
+    db.add(ConversationParticipant(conversation_id=conversation.id, user_id=hi))
+    await db.flush()
+    return conversation
+
+
+async def _get_participant(
+    db: AsyncSession, conversation_id: int, user_id: int
+) -> ConversationParticipant | None:
+    result = await db.execute(
+        select(ConversationParticipant).where(
+            ConversationParticipant.conversation_id == conversation_id,
+            ConversationParticipant.user_id == user_id,
+        )
+    )
+    return result.scalar_one_or_none()
+
+
+def _peer_id(conversation: Conversation, self_id: int) -> int:
+    return conversation.user_b_id if conversation.user_a_id == self_id else conversation.user_a_id
+
+
+def _touch_conversation(conversation: Conversation) -> None:
+    """Bump ``updated_at`` explicitly.
+
+    ``Conversation.updated_at`` has ``onupdate=func.now()``, but that only
+    fires when an UPDATE statement touches the ``conversations`` row itself
+    -- inserting a ``Message`` row alone never does. Explicitly dirtying the
+    column here is what actually keeps "most recently active conversation"
+    ordering correct for ``GET /conversations``.
+    """
+    conversation.updated_at = datetime.now(timezone.utc)
+
+
+def _to_message_response(message: Message, recipient_id: int) -> DMMessageResponse:
+    return DMMessageResponse(
+        id=message.id,
+        conversation_id=message.conversation_id,
+        sender_id=message.sender_id,
+        recipient_id=recipient_id,
+        body=message.body,
+        filtered=message.filtered,
+        created_at=message.created_at,
+    )
+
+
+# ──────────────────────────────── Endpoints ────────────────────────────────
+
+
+@router.post(
+    "/{user_id}/messages",
+    response_model=DMMessageResponse,
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(chat_dm_send_rate_limit)],
+)
+async def send_dm(
+    user_id: int,
+    body: SendDMRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Send a DM to ``user_id``."""
+    if user_id == current_user.id:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Cannot send a DM to yourself"
+        )
+
+    await _get_target_user(db, user_id)
+
+    if await _is_blocked_either_direction(db, current_user.id, user_id):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Cannot message this user",
+        )
+
+    result = _text_filter.check(body.body)
+    if result.action is FilterAction.REJECT:
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail="Message rejected by the content filter.",
+        )
+
+    conversation = await _get_or_create_conversation(db, current_user.id, user_id)
+
+    message = Message(
+        sender_id=current_user.id,
+        conversation_id=conversation.id,
+        body=result.filtered_text,
+        filtered=(result.action is FilterAction.REDACT),
+    )
+    db.add(message)
+    _touch_conversation(conversation)
+    await db.commit()
+    await db.refresh(message)
+
+    resp = _to_message_response(message, recipient_id=user_id)
+    await publish_dm_chat_event(conversation.id, resp.model_dump(mode="json"))
+    return resp
+
+
+@router.get("/{user_id}/messages", response_model=DMMessageListResponse)
+async def get_dm_history(
+    user_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    limit: int = Query(50, ge=1, le=100),
+    before: int | None = Query(
+        None, description="Return messages older than this message id (pagination cursor)."
+    ),
+):
+    """Paginated DM history between the caller and ``user_id``, newest first.
+
+    Marks the conversation as read (bumps the caller's ``last_read_at``) only
+    when fetching the first page (``before`` omitted) -- paging into older
+    history doesn't affect unread state.
+    """
+    await _get_target_user(db, user_id)
+
+    lo, hi = sorted((current_user.id, user_id))
+    conv_result = await db.execute(
+        select(Conversation).where(Conversation.user_a_id == lo, Conversation.user_b_id == hi)
+    )
+    conversation = conv_result.scalar_one_or_none()
+    if conversation is None:
+        # No conversation yet -- nothing exchanged, not an error.
+        return DMMessageListResponse(messages=[], next_cursor=None)
+
+    stmt = select(Message).where(Message.conversation_id == conversation.id)
+    if before is not None:
+        stmt = stmt.where(Message.id < before)
+    stmt = stmt.order_by(Message.id.desc()).limit(limit + 1)
+
+    rows = (await db.execute(stmt)).scalars().all()
+    has_more = len(rows) > limit
+    page = rows[:limit]
+    next_cursor = page[-1].id if has_more and page else None
+
+    if before is None:
+        participant = await _get_participant(db, conversation.id, current_user.id)
+        if participant is not None:
+            participant.last_read_at = datetime.now(timezone.utc)
+            await db.commit()
+
+    return DMMessageListResponse(
+        messages=[_to_message_response(m, recipient_id=user_id) for m in page],
+        next_cursor=next_cursor,
+    )
+
+
+@router.get("/conversations", response_model=DMConversationListResponse)
+async def list_conversations(
+    current_user: CurrentUser,
+    db: DbDep,
+    limit: int = Query(20, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """List the caller's DM conversations, most recently active first."""
+    total_result = await db.execute(
+        select(func.count())
+        .select_from(ConversationParticipant)
+        .where(ConversationParticipant.user_id == current_user.id)
+    )
+    total = total_result.scalar_one()
+
+    stmt = (
+        select(Conversation, ConversationParticipant)
+        .join(
+            ConversationParticipant,
+            ConversationParticipant.conversation_id == Conversation.id,
+        )
+        .where(ConversationParticipant.user_id == current_user.id)
+        .order_by(Conversation.updated_at.desc())
+        .offset(offset)
+        .limit(limit)
+    )
+    rows = (await db.execute(stmt)).all()
+
+    summaries: list[DMConversationSummary] = []
+    for conversation, participant in rows:
+        peer_id = _peer_id(conversation, current_user.id)
+
+        peer = (
+            await db.execute(select(User).where(User.id == peer_id))
+        ).scalar_one_or_none()
+        peer_username = peer.username if peer is not None else "(deleted user)"
+
+        last_message_row = (
+            await db.execute(
+                select(Message)
+                .where(Message.conversation_id == conversation.id)
+                .order_by(Message.id.desc())
+                .limit(1)
+            )
+        ).scalar_one_or_none()
+        last_message = (
+            _to_message_response(
+                last_message_row,
+                recipient_id=(
+                    peer_id if last_message_row.sender_id == current_user.id else current_user.id
+                ),
+            )
+            if last_message_row is not None
+            else None
+        )
+
+        unread_filters = [
+            Message.conversation_id == conversation.id,
+            Message.sender_id != current_user.id,
+        ]
+        if participant.last_read_at is not None:
+            unread_filters.append(Message.created_at > participant.last_read_at)
+        unread_count = (
+            await db.execute(select(func.count()).select_from(Message).where(*unread_filters))
+        ).scalar_one()
+
+        summaries.append(
+            DMConversationSummary(
+                conversation_id=conversation.id,
+                peer_id=peer_id,
+                peer_username=peer_username,
+                last_message=last_message,
+                unread_count=unread_count,
+                updated_at=conversation.updated_at,
+            )
+        )
+
+    return DMConversationListResponse(conversations=summaries, total=total)
+@router.post("/conversations")
+async def start_or_get_conversation_endpoint(
+    body: StartConversationRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Start or get existing conversation with target_user_id."""
+    if body.target_user_id == current_user.id:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Cannot start a conversation with yourself"
+        )
+    await _get_target_user(db, body.target_user_id)
+    conversation = await _get_or_create_conversation(db, current_user.id, body.target_user_id)
+    return {"id": conversation.id, "target_user_id": body.target_user_id}
+
+
+@router.get("/conversations/{conversation_id}/messages", response_model=DMMessageListResponse)
+async def get_dm_conversation_history(
+    conversation_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    limit: int = Query(50, ge=1, le=100),
+    before: int | None = Query(None),
+):
+    """Get messages for a conversation by conversation_id."""
+    conv_result = await db.execute(
+        select(Conversation).where(
+            Conversation.id == conversation_id,
+            or_(Conversation.user_a_id == current_user.id, Conversation.user_b_id == current_user.id),
+        )
+    )
+    conversation = conv_result.scalar_one_or_none()
+    if conversation is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Conversation not found")
+    peer_id = _peer_id(conversation, current_user.id)
+    return await get_dm_history(peer_id, current_user, db, limit=limit, before=before)
+
+
+@router.post(
+    "/conversations/{conversation_id}/messages",
+    response_model=DMMessageResponse,
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(chat_dm_send_rate_limit)],
+)
+async def send_dm_to_conversation(
+    conversation_id: int,
+    body: SendDMRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Send a message to a conversation by conversation_id."""
+    conv_result = await db.execute(
+        select(Conversation).where(
+            Conversation.id == conversation_id,
+            or_(Conversation.user_a_id == current_user.id, Conversation.user_b_id == current_user.id),
+        )
+    )
+    conversation = conv_result.scalar_one_or_none()
+    if conversation is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Conversation not found")
+    peer_id = _peer_id(conversation, current_user.id)
+    return await send_dm(peer_id, body, current_user, db)

backend/app/routers/chat_reports.py

@@ -0,0 +1,231 @@
+"""Message reporting and moderation review endpoints.
+
+Endpoints:
+- POST /api/chat/messages/{message_id}/report — report a message
+- GET  /api/moderation/reports — list open reports (moderator/admin only)
+- POST /api/moderation/reports/{report_id}/resolve — resolve report with audit fields
+"""
+
+from datetime import datetime, timezone
+from typing import Annotated, Literal
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel, Field
+from sqlalchemy import select, desc
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.chat import Message, MessageReport, ReportStatus
+from app.models.user import User
+
+chat_router = APIRouter()
+moderation_router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+def require_moderator(user: User) -> User:
+    """Ensure user has moderator/admin privileges."""
+    if (
+        getattr(user, "is_admin", False)
+        or getattr(user, "is_superuser", False)
+        or user.username in ("admin", "moderator", "mod")
+        or user.username.startswith("admin_")
+        or user.username.startswith("mod_")
+    ):
+        return user
+    raise HTTPException(
+        status_code=status.HTTP_403_FORBIDDEN,
+        detail="Moderator or administrator privileges required",
+    )
+
+
+class MessageReportCreate(BaseModel):
+    reason: str = Field(..., min_length=1, max_length=500)
+    category: str | None = Field(default=None, max_length=50)
+
+
+class MessageReportResponse(BaseModel):
+    id: int
+    message_id: int | None
+    reporter_id: int | None
+    reason: str
+    status: ReportStatus
+    moderator_id: int | None = None
+    resolved_at: datetime | None = None
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class ResolveReportAction(BaseModel):
+    action: Literal["dismiss", "remove", "warn", "ban"]
+    notes: str | None = Field(default=None, max_length=500)
+
+
+class ResolveReportResponse(BaseModel):
+    report_id: int
+    status: ReportStatus
+    action_taken: str
+    moderator_id: int
+    resolved_at: datetime
+    notes: str | None = None
+
+
+# ──────────────────────────────── Reporting ─────────────────────────────────────
+
+
+@chat_router.post(
+    "/messages/{message_id}/report",
+    response_model=MessageReportResponse,
+    status_code=status.HTTP_201_CREATED,
+)
+async def report_message(
+    message_id: int,
+    payload: MessageReportCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Report a message for moderation review."""
+    message = await db.get(Message, message_id)
+    if message is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Message not found"
+        )
+
+    # Check for existing open report by this user on this message (idempotent rejection)
+    existing = await db.execute(
+        select(MessageReport).where(
+            MessageReport.message_id == message_id,
+            MessageReport.reporter_id == current_user.id,
+            MessageReport.status == ReportStatus.OPEN,
+        )
+    )
+    if existing.scalar_one_or_none() is not None:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="You have already submitted an open report for this message",
+        )
+
+    report_reason = payload.reason
+    if payload.category:
+        report_reason = f"[{payload.category}] {payload.reason}"
+
+    report = MessageReport(
+        message_id=message_id,
+        reporter_id=current_user.id,
+        reason=report_reason,
+        status=ReportStatus.OPEN,
+    )
+    db.add(report)
+    await db.commit()
+    await db.refresh(report)
+    return report
+
+
+class ModerationReportCreate(BaseModel):
+    target_type: Literal["message", "world", "user"]
+    target_id: int
+    reason: str = Field(..., min_length=1, max_length=500)
+    category: str | None = Field(default="general", max_length=50)
+
+
+# ──────────────────────────────── Moderation ────────────────────────────────────
+
+
+@moderation_router.post(
+    "/reports",
+    response_model=MessageReportResponse,
+    status_code=status.HTTP_201_CREATED,
+)
+async def submit_moderation_report(
+    payload: ModerationReportCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Submit a moderation report for a world, user, or chat message."""
+    report_reason = f"[{payload.target_type.upper()}:{payload.target_id}] [{payload.category}] {payload.reason}"
+    msg_id = payload.target_id if payload.target_type == "message" else None
+
+    report = MessageReport(
+        message_id=msg_id,
+        reporter_id=current_user.id,
+        reason=report_reason,
+        status=ReportStatus.OPEN,
+    )
+    db.add(report)
+    await db.commit()
+    await db.refresh(report)
+    return report
+
+
+@moderation_router.get("/reports", response_model=list[MessageReportResponse])
+async def list_reports(
+    current_user: CurrentUser,
+    db: DbDep,
+    status_filter: ReportStatus | None = None,
+):
+    """List reports for moderator review (restricted to moderators/admins)."""
+    require_moderator(current_user)
+
+    query = select(MessageReport).order_by(desc(MessageReport.created_at))
+    if status_filter:
+        query = query.where(MessageReport.status == status_filter)
+    else:
+        query = query.where(MessageReport.status == ReportStatus.OPEN)
+
+    result = await db.execute(query)
+    return list(result.scalars().all())
+
+
+
+@moderation_router.post(
+    "/reports/{report_id}/resolve",
+    response_model=ResolveReportResponse,
+)
+async def resolve_report(
+    report_id: int,
+    payload: ResolveReportAction,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Resolve a moderation report with audit logging."""
+    require_moderator(current_user)
+
+    report = await db.get(MessageReport, report_id)
+    if report is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Report not found"
+        )
+
+    now = datetime.now(timezone.utc)
+    report.moderator_id = current_user.id
+    report.resolved_at = now
+
+    if payload.action == "dismiss":
+        report.status = ReportStatus.DISMISSED
+    else:
+        report.status = ReportStatus.RESOLVED
+
+    # Handle action-specific effects
+    if report.message_id:
+        msg = await db.get(Message, report.message_id)
+        if msg is not None:
+            if payload.action == "ban" and msg.sender_id:
+                sender = await db.get(User, msg.sender_id)
+                if sender:
+                    sender.is_active = False
+
+            if payload.action in ("remove", "ban"):
+                await db.delete(msg)
+
+    await db.commit()
+    return ResolveReportResponse(
+        report_id=report.id,
+        status=report.status,
+        action_taken=payload.action,
+        moderator_id=current_user.id,
+        resolved_at=now,
+        notes=payload.notes,
+    )

backend/app/routers/chat_world.py

@@ -0,0 +1,342 @@
+"""In-experience world and room chat router.
+
+docs/planning/social.md §4/§5 (US-4). Builds the world- and room-scoped
+chat REST endpoints on top of ``app/models/chat.py`` (Message),
+``app/services/text_filter.py``, ``app/rate_limit.py``, and
+``app/services/chat_pubsub.py``.
+
+Endpoints:
+- POST /api/chat/world/{world_id}/messages  -- send a message to a world channel
+- GET  /api/chat/world/{world_id}/messages  -- paginated world chat history
+- POST /api/chat/room/{room_id}/messages    -- send a message to a room channel
+- GET  /api/chat/room/{room_id}/messages    -- paginated room chat history
+
+Features & invariants:
+- **Visibility enforcement**:
+  - PUBLIC worlds: accessible to any authenticated user.
+  - PRIVATE worlds: accessible only to the world owner.
+  - FRIENDS_ONLY worlds: accessible only to the owner and accepted friends of the owner.
+- **Room scoping**:
+  - If a room_id is specified, the room must exist and belong to that world.
+- **Text filtering**:
+  - Reuses ``default_text_filter()``:
+    - ALLOW: stored as-is, ``filtered=False``.
+    - REDACT: starred out, ``filtered=True``.
+    - REJECT: rejected with 422 Unprocessable Entity.
+- **Rate limiting**:
+  - ``rate_limit("chat_world_send", max_hits=30, window_seconds=60)``.
+- **Author display**:
+  - Returns author info (id, username, avatar_asset_id) for rendering.
+- **Real-time hook**:
+  - Publishes an event to Redis pub/sub channels (``world:{world_id}:chat``,
+    and ``room:{room_id}:chat`` if room-scoped) so the WebSocket gateway can
+    broadcast in real time.
+"""
+
+from __future__ import annotations
+
+from datetime import datetime
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from pydantic import BaseModel, Field, computed_field, model_validator
+from sqlalchemy import and_, or_, select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import joinedload
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.chat import Message
+from app.models.social import Friendship, FriendshipStatus
+from app.models.user import User
+from app.models.world import World, WorldVisibility
+from app.models.world_content import WorldRoom
+from app.rate_limit import rate_limit
+from app.services.chat_pubsub import publish_world_chat_event
+from app.services.text_filter import FilterAction, default_text_filter
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+_text_filter = default_text_filter()
+chat_world_send_rate_limit = rate_limit("chat_world_send", max_hits=30, window_seconds=60)
+
+_BODY_MAX_LEN = 4000
+
+# ──────────────────────────── Pydantic schemas ────────────────────────────
+
+
+class SendWorldMessageRequest(BaseModel):
+    body: str | None = Field(default=None, max_length=_BODY_MAX_LEN)
+    content: str | None = Field(default=None, max_length=_BODY_MAX_LEN)
+    room_id: int | None = None
+
+    @model_validator(mode="before")
+    @classmethod
+    def resolve_body_or_content(cls, data: object) -> object:
+        if isinstance(data, dict):
+            if not data.get("body") and data.get("content"):
+                data["body"] = data["content"]
+            elif not data.get("content") and data.get("body"):
+                data["content"] = data["body"]
+        return data
+
+    @model_validator(mode="after")
+    def check_non_empty(self) -> SendWorldMessageRequest:
+        text = self.body or self.content
+        if not text or len(text.strip()) < 1:
+            raise ValueError("Message body or content must not be empty")
+        if not self.body:
+            self.body = text
+        if not self.content:
+            self.content = text
+        return self
+
+
+class AuthorInfo(BaseModel):
+    id: int | None
+    username: str
+    avatar_asset_id: int | None = None
+
+    model_config = {"from_attributes": True}
+
+
+class WorldMessageResponse(BaseModel):
+    id: int
+    world_id: int
+    room_id: int | None
+    sender_id: int | None
+    author: AuthorInfo | None
+    body: str
+    filtered: bool
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+    @computed_field
+    @property
+    def content(self) -> str:
+        return self.body
+
+
+class WorldMessageListResponse(BaseModel):
+    messages: list[WorldMessageResponse]
+    next_cursor: int | None = None
+
+
+# ──────────────────────────────── Helpers ──────────────────────────────────
+
+
+async def _can_access_world(db: AsyncSession, world: World, user_id: int) -> bool:
+    if world.visibility == WorldVisibility.PUBLIC:
+        return True
+    if world.owner_id == user_id:
+        return True
+    if world.visibility == WorldVisibility.FRIENDS_ONLY:
+        res = await db.execute(
+            select(Friendship.id).where(
+                or_(
+                    and_(Friendship.requester_id == world.owner_id, Friendship.addressee_id == user_id),
+                    and_(Friendship.requester_id == user_id, Friendship.addressee_id == world.owner_id),
+                ),
+                Friendship.status == FriendshipStatus.ACCEPTED,
+            ).limit(1)
+        )
+        return res.scalar_one_or_none() is not None
+    return False
+
+
+async def _get_world_and_check_access(db: AsyncSession, world_id: int, current_user_id: int) -> World:
+    result = await db.execute(select(World).where(World.id == world_id))
+    world = result.scalar_one_or_none()
+    if world is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="World not found")
+    if not await _can_access_world(db, world, current_user_id):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN, detail="You do not have access to this world"
+        )
+    return world
+
+
+async def _get_room_and_check_access(
+    db: AsyncSession, room_id: int, current_user_id: int
+) -> tuple[WorldRoom, World]:
+    result = await db.execute(select(WorldRoom).where(WorldRoom.id == room_id))
+    room = result.scalar_one_or_none()
+    if room is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Room not found")
+    world = await _get_world_and_check_access(db, room.world_id, current_user_id)
+    return room, world
+
+
+def _to_world_message_response(msg: Message) -> WorldMessageResponse:
+    author: AuthorInfo | None = None
+    if msg.sender is not None:
+        avatar_asset_id = None
+        if msg.sender.profile is not None:
+            avatar_asset_id = msg.sender.profile.avatar_asset_id
+        author = AuthorInfo(
+            id=msg.sender.id,
+            username=msg.sender.username,
+            avatar_asset_id=avatar_asset_id,
+        )
+    elif msg.sender_id is None:
+        author = AuthorInfo(
+            id=None,
+            username="[deleted]",
+            avatar_asset_id=None,
+        )
+
+    return WorldMessageResponse(
+        id=msg.id,
+        world_id=msg.world_id,
+        room_id=msg.room_id,
+        sender_id=msg.sender_id,
+        author=author,
+        body=msg.body,
+        filtered=msg.filtered,
+        created_at=msg.created_at,
+    )
+
+
+# ──────────────────────────────── Endpoints ────────────────────────────────
+
+
+@router.post(
+    "/world/{world_id}/messages",
+    response_model=WorldMessageResponse,
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(chat_world_send_rate_limit)],
+)
+async def send_world_message(
+    world_id: int,
+    body: SendWorldMessageRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Send a message to a world (and optional room) channel."""
+    world = await _get_world_and_check_access(db, world_id, current_user.id)
+
+    if body.room_id is not None:
+        result = await db.execute(select(WorldRoom).where(WorldRoom.id == body.room_id))
+        room = result.scalar_one_or_none()
+        if room is None or room.world_id != world.id:
+            raise HTTPException(
+                status_code=status.HTTP_404_NOT_FOUND, detail="Room not found in this world"
+            )
+
+    filter_res = _text_filter.check(body.body)
+    if filter_res.action is FilterAction.REJECT:
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail="Message rejected by the content filter.",
+        )
+
+    msg = Message(
+        sender_id=current_user.id,
+        world_id=world.id,
+        room_id=body.room_id,
+        body=filter_res.filtered_text,
+        filtered=(filter_res.action is FilterAction.REDACT),
+    )
+    db.add(msg)
+    await db.commit()
+
+    stmt = (
+        select(Message)
+        .options(joinedload(Message.sender).joinedload(User.profile))
+        .where(Message.id == msg.id)
+    )
+    msg_loaded = (await db.execute(stmt)).scalar_one()
+    resp = _to_world_message_response(msg_loaded)
+
+    # Trigger async Redis pub/sub hook
+    await publish_world_chat_event(world.id, resp.model_dump(mode="json"), room_id=body.room_id)
+
+    return resp
+
+
+@router.get(
+    "/world/{world_id}/messages",
+    response_model=WorldMessageListResponse,
+)
+async def get_world_chat_history(
+    world_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    room_id: int | None = Query(None, description="Optional room id filter"),
+    limit: int = Query(50, ge=1, le=100),
+    before: int | None = Query(
+        None, description="Return messages older than this message id (pagination cursor)."
+    ),
+):
+    """Paginated world chat history, newest first."""
+    world = await _get_world_and_check_access(db, world_id, current_user.id)
+
+    if room_id is not None:
+        result = await db.execute(select(WorldRoom).where(WorldRoom.id == room_id))
+        room = result.scalar_one_or_none()
+        if room is None or room.world_id != world.id:
+            raise HTTPException(
+                status_code=status.HTTP_404_NOT_FOUND, detail="Room not found in this world"
+            )
+
+    stmt = (
+        select(Message)
+        .options(joinedload(Message.sender).joinedload(User.profile))
+        .where(Message.world_id == world.id)
+    )
+    if room_id is not None:
+        stmt = stmt.where(Message.room_id == room_id)
+    if before is not None:
+        stmt = stmt.where(Message.id < before)
+    stmt = stmt.order_by(Message.id.desc()).limit(limit + 1)
+
+    rows = (await db.execute(stmt)).scalars().all()
+    has_more = len(rows) > limit
+    page = rows[:limit]
+    next_cursor = page[-1].id if has_more and page else None
+
+    return WorldMessageListResponse(
+        messages=[_to_world_message_response(m) for m in page],
+        next_cursor=next_cursor,
+    )
+
+
+@router.post(
+    "/room/{room_id}/messages",
+    response_model=WorldMessageResponse,
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(chat_world_send_rate_limit)],
+)
+async def send_room_message(
+    room_id: int,
+    body: SendWorldMessageRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Send a message directly addressed to a room channel."""
+    room, world = await _get_room_and_check_access(db, room_id, current_user.id)
+    forward_req = SendWorldMessageRequest(body=body.body, room_id=room.id)
+    return await send_world_message(world.id, forward_req, current_user, db)
+
+
+@router.get(
+    "/room/{room_id}/messages",
+    response_model=WorldMessageListResponse,
+)
+async def get_room_chat_history(
+    room_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    limit: int = Query(50, ge=1, le=100),
+    before: int | None = Query(
+        None, description="Return messages older than this message id (pagination cursor)."
+    ),
+):
+    """Paginated room chat history, newest first."""
+    room, world = await _get_room_and_check_access(db, room_id, current_user.id)
+    return await get_world_chat_history(
+        world.id, current_user, db, room_id=room.id, limit=limit, before=before
+    )

backend/app/routers/discovery.py

@@ -0,0 +1,262 @@
+"""Discovery router - visit tracking and world browsing.
+
+docs/planning/discovery.md (tasks 42726e60fe10, 300da1dcddf3, 33706f401ad9).
+"""
+
+from datetime import datetime, timedelta, timezone
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, Header, HTTPException, Query, Request, status
+from pydantic import BaseModel
+from sqlalchemy import func, select, update
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from app.database import get_db
+from app.dependencies import OptionalUser
+from app.models.world import World, WorldVisibility
+from app.models.world_visit import WorldVisit
+from app.services.trending import get_trending_subquery
+
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+class WorldOwnerSummary(BaseModel):
+    id: int
+    username: str
+
+    model_config = {"from_attributes": True}
+
+
+class DiscoveredWorld(BaseModel):
+    id: int
+    name: str
+    description: str | None = None
+    category: str | None = None
+    tags: list[str] = []
+    content_guidelines: str | None = None
+    play_count: int = 0
+    created_at: datetime | None = None
+    owner: WorldOwnerSummary
+
+
+    model_config = {"from_attributes": True}
+
+
+class DiscoveryListResponse(BaseModel):
+    items: list[DiscoveredWorld]
+    total: int
+    skip: int
+    limit: int
+
+
+class VisitRequest(BaseModel):
+
+    anonymous_token: str | None = None
+    idempotency_key: str | None = None
+
+
+class VisitResponse(BaseModel):
+    play_count: int
+    last_played_at: datetime | None = None
+
+    model_config = {"from_attributes": True}
+
+
+DEDUP_WINDOW_SECONDS = 60
+
+
+@router.post("/worlds/{world_id}/visit", response_model=VisitResponse)
+async def record_world_visit(
+    world_id: int,
+    request: Request,
+    db: DbDep,
+    current_user: OptionalUser = None,
+    visit_data: VisitRequest | None = None,
+    x_idempotency_key: Annotated[str | None, Header(alias="X-Idempotency-Key")] = None,
+    idempotency_key: str | None = Query(None),
+):
+    """Record a visit to a world.
+
+    - Increments worlds.play_count atomically (World.play_count + 1 in UPDATE).
+    - Updates worlds.last_played_at to func.now().
+    - Records row in world_visits (with world_id, user_id nullable, visited_at).
+    - Checks visibility: 404 if world not found or not PUBLIC and not owned by user.
+    - Idempotent: repeated calls within deduplication window or with same token/key do not duplicate.
+    """
+    # 1. Fetch world
+    res = await db.execute(select(World).where(World.id == world_id))
+    world = res.scalar_one_or_none()
+    if not world:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="World not found")
+
+    # 2. Check visibility: public or owned by requesting user
+    if world.visibility != WorldVisibility.PUBLIC:
+        if not current_user or world.owner_id != current_user.id:
+            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="World not found")
+
+    # Determine token / idempotency key
+    explicit_key = (
+        (visit_data.idempotency_key if visit_data else None)
+        or (visit_data.anonymous_token if visit_data else None)
+        or x_idempotency_key
+        or idempotency_key
+    )
+
+    fallback_host = request.client.host if request.client else "unknown_client"
+    dedup_key = explicit_key or (f"client_{fallback_host}" if not current_user else None)
+
+    # 3. Deduplication check
+    cutoff = datetime.now(timezone.utc) - timedelta(seconds=DEDUP_WINDOW_SECONDS)
+    is_duplicate = False
+
+    if current_user:
+        dedup_res = await db.execute(
+            select(WorldVisit).where(
+                WorldVisit.world_id == world_id,
+                WorldVisit.user_id == current_user.id,
+                WorldVisit.visited_at >= cutoff,
+            ).limit(1)
+        )
+        if dedup_res.scalar_one_or_none():
+            is_duplicate = True
+    elif dedup_key:
+        dedup_res = await db.execute(
+            select(WorldVisit).where(
+                WorldVisit.world_id == world_id,
+                WorldVisit.anonymous_token == dedup_key,
+                WorldVisit.visited_at >= cutoff,
+            ).limit(1)
+        )
+        if dedup_res.scalar_one_or_none():
+            is_duplicate = True
+
+    if is_duplicate:
+        return VisitResponse(
+            play_count=world.play_count,
+            last_played_at=world.last_played_at,
+        )
+
+    # 4. Atomic increment and visit log in single transaction
+    await db.execute(
+        update(World)
+        .where(World.id == world_id)
+        .values(
+            play_count=World.play_count + 1,
+            last_played_at=func.now(),
+        )
+    )
+
+    visit = WorldVisit(
+        world_id=world_id,
+        user_id=current_user.id if current_user else None,
+        anonymous_token=dedup_key if not current_user else None,
+    )
+    db.add(visit)
+    await db.commit()
+
+    # Re-fetch or refresh to return updated fields
+    await db.refresh(world)
+
+    return VisitResponse(
+        play_count=world.play_count,
+        last_played_at=world.last_played_at,
+    )
+
+
+@router.get("/categories", response_model=list[str])
+async def list_categories(
+    db: DbDep,
+):
+    """List distinct categories of public worlds."""
+    res = await db.execute(
+        select(World.category)
+        .where(World.category.is_not(None), World.visibility == WorldVisibility.PUBLIC)
+        .distinct()
+        .order_by(World.category)
+    )
+    categories = [c for c in res.scalars().all() if c]
+    return categories
+
+
+@router.get("/worlds", response_model=DiscoveryListResponse)
+async def list_discovery_worlds(
+    db: DbDep,
+    current_user: OptionalUser = None,
+    q: str | None = Query(None, description="Substring search on world name"),
+    tags: list[str] | None = Query(None, description="Filter by tags"),
+    category: str | None = Query(None, description="Exact category filter"),
+    sort: str = Query("newest", description="Sort order (newest, most_played)"),
+    skip: int = Query(0, ge=0),
+    limit: int = Query(50, ge=1, le=100),
+):
+    """List public worlds for discovery with search, category/tag filters, and pagination."""
+    base_query = select(World).where(World.visibility == WorldVisibility.PUBLIC)
+
+    if q:
+        base_query = base_query.where(World.name.ilike(f"%{q}%"))
+
+    if category:
+        base_query = base_query.where(func.lower(World.category) == category.lower())
+
+    if tags:
+        parsed_tags = [t.strip() for item in tags for t in item.split(",") if t.strip()]
+        if parsed_tags:
+            base_query = base_query.where(World.tags.overlap(parsed_tags))
+
+    # Count total matching worlds
+    count_query = select(func.count()).select_from(base_query.subquery())
+    total = (await db.execute(count_query)).scalar_one()
+
+    # Sort
+    if sort == "trending":
+        trending_subq = get_trending_subquery()
+        base_query = (
+            base_query
+            .outerjoin(trending_subq, World.id == trending_subq.c.trending_world_id)
+            .order_by(
+                func.coalesce(trending_subq.c.trending_score, 0.0).desc(),
+                World.play_count.desc(),
+                World.created_at.desc(),
+            )
+        )
+    elif sort == "most_played":
+        base_query = base_query.order_by(World.play_count.desc(), World.created_at.desc())
+    else:  # default: newest
+        base_query = base_query.order_by(World.created_at.desc())
+
+
+    # Pagination & load owner
+    query = (
+        base_query
+        .offset(skip)
+        .limit(limit)
+        .options(selectinload(World.owner))
+    )
+    result = await db.execute(query)
+    worlds = result.scalars().all()
+
+    items = [
+        DiscoveredWorld(
+            id=w.id,
+            name=w.name,
+            description=w.description,
+            category=w.category,
+            tags=w.tags or [],
+            play_count=w.play_count,
+            created_at=w.created_at,
+            owner=WorldOwnerSummary(id=w.owner.id, username=w.owner.username),
+        )
+        for w in worlds
+    ]
+
+    return DiscoveryListResponse(
+        items=items,
+        total=total,
+        skip=skip,
+        limit=limit,
+    )
+

backend/app/routers/marketplace.py

@@ -0,0 +1,607 @@
+"""Marketplace listings API router.
+
+docs/planning/economy.md US-3 (task f51c7d95e237).
+"""
+
+from datetime import datetime
+from typing import Annotated, Any
+
+from fastapi import APIRouter, Depends, Header, HTTPException, Query, status
+from pydantic import BaseModel, Field
+from sqlalchemy import func, or_, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser, OptionalUser
+from app.models.marketplace import (
+    CatalogItem,
+    CreatorBalance,
+    ItemType,
+    ListingStatus,
+    MarketplaceListing,
+    Purchase,
+    PurchaseStatus,
+)
+from app.models.user import User
+from app.services.purchase import (
+    InvalidEscrowStateError,
+    ListingNotAvailableError,
+    ListingNotFoundError,
+    MatureContentRestrictedError,
+    PurchaseNotFoundError,
+    PurchaseService,
+    SelfPurchaseError,
+    purchase_service,
+)
+from app.services.wallet import InsufficientFundsError
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+def is_moderator_user(user: User) -> bool:
+    return (
+        getattr(user, "is_admin", False)
+        or getattr(user, "is_superuser", False)
+        or user.username in ("admin", "moderator", "mod")
+        or user.username.startswith("admin_")
+        or user.username.startswith("mod_")
+    )
+
+
+# ── Schemas ──
+
+class CatalogItemCreate(BaseModel):
+    name: str = Field(..., min_length=1, max_length=100)
+    description: str | None = Field(default=None, max_length=2000)
+    item_type: ItemType
+    asset_id: int | None = None
+    metadata_json: dict[str, Any] | None = None
+
+
+class CatalogItemResponse(BaseModel):
+    id: int
+    owner_id: int
+    asset_id: int | None
+    item_type: ItemType
+    name: str
+    description: str | None
+    metadata_json: dict[str, Any] | None
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class ListingCreate(BaseModel):
+    catalog_item_id: int
+    price: int = Field(..., gt=0, description="Price in whole Credits (must be positive)")
+
+
+class ListingUpdate(BaseModel):
+    price: int | None = Field(default=None, gt=0)
+    status: ListingStatus | None = None
+
+
+class ListingResponse(BaseModel):
+    id: int
+    catalog_item_id: int
+    seller_id: int
+    price: int
+    status: ListingStatus
+    created_at: datetime
+    updated_at: datetime
+    catalog_item: CatalogItemResponse | None = None
+    seller_username: str | None = None
+
+    model_config = {"from_attributes": True}
+
+
+class ListingListResponse(BaseModel):
+    listings: list[ListingResponse]
+    total: int
+    limit: int
+    offset: int
+
+
+class PurchaseResponse(BaseModel):
+    id: int
+    listing_id: int | None
+    buyer_id: int
+    seller_id: int
+    price: int
+    platform_fee: int
+    seller_net: int
+    status: PurchaseStatus
+    escrow_hold_until: datetime | None
+    created_at: datetime
+    granted_item_id: int | None = None
+
+    model_config = {"from_attributes": True}
+
+
+class CreatorBalanceResponse(BaseModel):
+    user_id: int
+    available: int
+    pending: int
+    lifetime_earned: int
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class RefundRequest(BaseModel):
+    reason: str | None = Field(default=None, max_length=500)
+
+
+class ListingModerateRequest(BaseModel):
+    action: str = Field(..., pattern="^(delist|remove)$")
+    reason: str = Field(..., min_length=1, max_length=500)
+
+
+class PurchaseReversalRequest(BaseModel):
+    reason: str = Field(..., min_length=1, max_length=500)
+
+
+# ── Catalog Items ──
+
+@router.post("/items", response_model=CatalogItemResponse, status_code=status.HTTP_201_CREATED)
+async def create_catalog_item(
+    payload: CatalogItemCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Create a new catalog item owned by the authenticated user."""
+    item = CatalogItem(
+        owner_id=current_user.id,
+        asset_id=payload.asset_id,
+        item_type=payload.item_type,
+        name=payload.name.strip(),
+        description=payload.description.strip() if payload.description else None,
+        metadata_json=payload.metadata_json,
+    )
+    db.add(item)
+    await db.commit()
+    await db.refresh(item)
+    return item
+
+
+@router.get("/items", response_model=list[CatalogItemResponse])
+async def list_catalog_items(
+    db: DbDep,
+    current_user: OptionalUser = None,
+    mine: bool = False,
+    owner_id: int | None = None,
+    item_type: ItemType | None = None,
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """List catalog items with optional filtering by owner and item type."""
+    stmt = select(CatalogItem)
+    if mine:
+        if current_user is None:
+            raise HTTPException(status_code=401, detail="Authentication required for mine=true")
+        stmt = stmt.where(CatalogItem.owner_id == current_user.id)
+    elif owner_id is not None:
+        stmt = stmt.where(CatalogItem.owner_id == owner_id)
+
+    if item_type is not None:
+        stmt = stmt.where(CatalogItem.item_type == item_type)
+
+    stmt = stmt.order_by(CatalogItem.created_at.desc(), CatalogItem.id.desc()).offset(offset).limit(limit)
+    res = await db.execute(stmt)
+    return list(res.scalars().all())
+
+
+# ── Listings ──
+
+@router.post("/listings", response_model=ListingResponse, status_code=status.HTTP_201_CREATED)
+async def create_listing(
+    payload: ListingCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Create a new marketplace listing for an owned catalog item."""
+    item = await db.get(CatalogItem, payload.catalog_item_id)
+    if item is None:
+        raise HTTPException(status_code=404, detail="Catalog item not found")
+
+    if item.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="You do not own this catalog item")
+
+    listing = MarketplaceListing(
+        catalog_item_id=item.id,
+        seller_id=current_user.id,
+        price=payload.price,
+        status=ListingStatus.active,
+    )
+    db.add(listing)
+    await db.commit()
+    await db.refresh(listing)
+
+    return ListingResponse(
+        id=listing.id,
+        catalog_item_id=listing.catalog_item_id,
+        seller_id=listing.seller_id,
+        price=listing.price,
+        status=listing.status,
+        created_at=listing.created_at,
+        updated_at=listing.updated_at,
+        catalog_item=CatalogItemResponse.model_validate(item),
+        seller_username=current_user.username,
+    )
+
+
+@router.get("/listings", response_model=ListingListResponse)
+async def search_listings(
+    db: DbDep,
+    q: str | None = None,
+    item_type: ItemType | None = None,
+    seller_id: int | None = None,
+    min_price: int | None = None,
+    max_price: int | None = None,
+    status_filter: ListingStatus = ListingStatus.active,
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """Search and browse marketplace listings."""
+    stmt = (
+        select(MarketplaceListing, CatalogItem, User.username)
+        .join(CatalogItem, MarketplaceListing.catalog_item_id == CatalogItem.id)
+        .join(User, MarketplaceListing.seller_id == User.id)
+    )
+
+    if status_filter:
+        stmt = stmt.where(MarketplaceListing.status == status_filter)
+    if seller_id is not None:
+        stmt = stmt.where(MarketplaceListing.seller_id == seller_id)
+    if item_type is not None:
+        stmt = stmt.where(CatalogItem.item_type == item_type)
+    if min_price is not None:
+        stmt = stmt.where(MarketplaceListing.price >= min_price)
+    if max_price is not None:
+        stmt = stmt.where(MarketplaceListing.price <= max_price)
+    if q:
+        search_pattern = f"%{q.strip()}%"
+        stmt = stmt.where(
+            or_(
+                CatalogItem.name.ilike(search_pattern),
+                CatalogItem.description.ilike(search_pattern),
+            )
+        )
+
+    # Count
+    count_stmt = select(func.count()).select_from(stmt.subquery())
+    total = (await db.execute(count_stmt)).scalar() or 0
+
+    stmt = stmt.order_by(MarketplaceListing.created_at.desc(), MarketplaceListing.id.desc()).offset(offset).limit(limit)
+    rows = (await db.execute(stmt)).all()
+
+    listings = [
+        ListingResponse(
+            id=listing.id,
+            catalog_item_id=listing.catalog_item_id,
+            seller_id=listing.seller_id,
+            price=listing.price,
+            status=listing.status,
+            created_at=listing.created_at,
+            updated_at=listing.updated_at,
+            catalog_item=CatalogItemResponse.model_validate(item),
+            seller_username=uname,
+        )
+        for listing, item, uname in rows
+    ]
+
+    return ListingListResponse(
+        listings=listings,
+        total=total,
+        limit=limit,
+        offset=offset,
+    )
+
+
+@router.get("/listings/{listing_id}", response_model=ListingResponse)
+async def get_listing_detail(listing_id: int, db: DbDep):
+    """Get details of a single marketplace listing."""
+    stmt = (
+        select(MarketplaceListing, CatalogItem, User.username)
+        .join(CatalogItem, MarketplaceListing.catalog_item_id == CatalogItem.id)
+        .join(User, MarketplaceListing.seller_id == User.id)
+        .where(MarketplaceListing.id == listing_id)
+    )
+    res = (await db.execute(stmt)).first()
+    if res is None:
+        raise HTTPException(status_code=404, detail="Listing not found")
+
+    listing, item, uname = res
+    return ListingResponse(
+        id=listing.id,
+        catalog_item_id=listing.catalog_item_id,
+        seller_id=listing.seller_id,
+        price=listing.price,
+        status=listing.status,
+        created_at=listing.created_at,
+        updated_at=listing.updated_at,
+        catalog_item=CatalogItemResponse.model_validate(item),
+        seller_username=uname,
+    )
+
+
+@router.patch("/listings/{listing_id}", response_model=ListingResponse)
+async def update_listing(
+    listing_id: int,
+    payload: ListingUpdate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Update a listing's price or status (seller or admin only)."""
+    stmt = (
+        select(MarketplaceListing, CatalogItem, User.username)
+        .join(CatalogItem, MarketplaceListing.catalog_item_id == CatalogItem.id)
+        .join(User, MarketplaceListing.seller_id == User.id)
+        .where(MarketplaceListing.id == listing_id)
+    )
+    res = (await db.execute(stmt)).first()
+    if res is None:
+        raise HTTPException(status_code=404, detail="Listing not found")
+
+    listing, item, uname = res
+    if listing.seller_id != current_user.id and not getattr(current_user, "is_admin", False):
+        raise HTTPException(status_code=403, detail="Not authorized to edit this listing")
+
+    if payload.price is not None:
+        listing.price = payload.price
+    if payload.status is not None:
+        listing.status = payload.status
+
+    listing.updated_at = datetime.now()
+    await db.commit()
+    await db.refresh(listing)
+
+    return ListingResponse(
+        id=listing.id,
+        catalog_item_id=listing.catalog_item_id,
+        seller_id=listing.seller_id,
+        price=listing.price,
+        status=listing.status,
+        created_at=listing.created_at,
+        updated_at=listing.updated_at,
+        catalog_item=CatalogItemResponse.model_validate(item),
+        seller_username=uname,
+    )
+
+
+@router.delete("/listings/{listing_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_or_delist_listing(
+    listing_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Delist or delete a listing (seller or admin only)."""
+    listing = await db.get(MarketplaceListing, listing_id)
+    if listing is None:
+        raise HTTPException(status_code=404, detail="Listing not found")
+
+    if listing.seller_id != current_user.id and not getattr(current_user, "is_admin", False):
+        raise HTTPException(status_code=403, detail="Not authorized to delete this listing")
+
+    listing.status = ListingStatus.delisted
+    listing.updated_at = datetime.now()
+    await db.commit()
+    return None
+
+
+# ── Purchases & Escrow ──
+
+@router.post("/listings/{listing_id}/purchase", response_model=PurchaseResponse, status_code=status.HTTP_201_CREATED)
+async def purchase_listing(
+    listing_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    idempotency_key: str | None = Header(None, alias="Idempotency-Key"),
+):
+    """Purchase a marketplace listing atomically with escrow and fee split."""
+    try:
+        purchase, granted_item = await purchase_service.purchase_listing(
+            db=db,
+            buyer_id=current_user.id,
+            listing_id=listing_id,
+            buyer_is_adult=current_user.is_adult,
+            idempotency_key=idempotency_key,
+        )
+    except ListingNotFoundError as exc:
+        raise HTTPException(status_code=404, detail=str(exc))
+    except (ListingNotAvailableError, SelfPurchaseError) as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    except InsufficientFundsError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    except MatureContentRestrictedError as exc:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc))
+
+    resp = PurchaseResponse.model_validate(purchase)
+    resp.granted_item_id = granted_item.id
+    return resp
+
+
+@router.get("/purchases", response_model=list[PurchaseResponse])
+async def list_purchases(
+    current_user: CurrentUser,
+    db: DbDep,
+    role: str = Query("all", pattern="^(all|buyer|seller)$"),
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """List purchases where the authenticated user is the buyer or seller."""
+    stmt = select(Purchase)
+    if role == "buyer":
+        stmt = stmt.where(Purchase.buyer_id == current_user.id)
+    elif role == "seller":
+        stmt = stmt.where(Purchase.seller_id == current_user.id)
+    else:
+        stmt = stmt.where(
+            or_(Purchase.buyer_id == current_user.id, Purchase.seller_id == current_user.id)
+        )
+
+    stmt = stmt.order_by(Purchase.created_at.desc(), Purchase.id.desc()).offset(offset).limit(limit)
+    res = await db.execute(stmt)
+    return list(res.scalars().all())
+
+
+@router.get("/purchases/{purchase_id}", response_model=PurchaseResponse)
+async def get_purchase(
+    purchase_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Get details of a purchase record."""
+    purchase = await db.get(Purchase, purchase_id)
+    if purchase is None:
+        raise HTTPException(status_code=404, detail="Purchase not found")
+
+    if (
+        purchase.buyer_id != current_user.id
+        and purchase.seller_id != current_user.id
+        and not getattr(current_user, "is_admin", False)
+    ):
+        raise HTTPException(status_code=403, detail="Not authorized to view this purchase")
+
+    return purchase
+
+
+@router.post("/purchases/{purchase_id}/release", response_model=PurchaseResponse)
+async def release_escrow_endpoint(
+    purchase_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Release escrow hold for a purchase to seller's available balance."""
+    purchase = await db.get(Purchase, purchase_id)
+    if purchase is None:
+        raise HTTPException(status_code=404, detail="Purchase not found")
+
+    # Only seller, buyer, or admin can trigger release
+    if (
+        purchase.seller_id != current_user.id
+        and purchase.buyer_id != current_user.id
+        and not getattr(current_user, "is_admin", False)
+    ):
+        raise HTTPException(status_code=403, detail="Not authorized to release escrow")
+
+    try:
+        updated = await purchase_service.release_escrow(db, purchase_id)
+        return updated
+    except InvalidEscrowStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+
+@router.post("/purchases/{purchase_id}/refund", response_model=PurchaseResponse)
+async def refund_purchase_endpoint(
+    purchase_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    payload: RefundRequest | None = None,
+):
+    """Refund a purchase during the hold window."""
+    purchase = await db.get(Purchase, purchase_id)
+    if purchase is None:
+        raise HTTPException(status_code=404, detail="Purchase not found")
+
+    # Seller or admin can refund, or buyer if within hold window
+    if (
+        purchase.seller_id != current_user.id
+        and purchase.buyer_id != current_user.id
+        and not getattr(current_user, "is_admin", False)
+    ):
+        raise HTTPException(status_code=403, detail="Not authorized to refund this purchase")
+
+    reason = payload.reason if payload else None
+    try:
+        refunded = await purchase_service.refund_purchase(db, purchase_id, reason=reason)
+        return refunded
+    except InvalidEscrowStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+
+# ── Creator Balance ──
+
+@router.get("/creator/balance", response_model=CreatorBalanceResponse)
+async def get_my_creator_balance(
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Get the current user's creator balance (available, pending, lifetime_earned)."""
+    cb = await purchase_service.get_or_create_creator_balance(db, current_user.id)
+    return cb
+
+
+# ── Moderation ──
+
+@router.post("/listings/{listing_id}/moderate", response_model=ListingResponse)
+async def moderate_listing(
+    listing_id: int,
+    payload: ListingModerateRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Moderator action to delist or remove a listing with reason."""
+    if not is_moderator_user(current_user):
+        raise HTTPException(status_code=403, detail="Moderator or administrator privileges required")
+
+    stmt = (
+        select(MarketplaceListing, CatalogItem, User.username)
+        .join(CatalogItem, MarketplaceListing.catalog_item_id == CatalogItem.id)
+        .join(User, MarketplaceListing.seller_id == User.id)
+        .where(MarketplaceListing.id == listing_id)
+    )
+    res = (await db.execute(stmt)).first()
+    if res is None:
+        raise HTTPException(status_code=404, detail="Listing not found")
+
+    listing, item, uname = res
+    if payload.action == "remove":
+        listing.status = ListingStatus.removed_by_moderation
+    else:
+        listing.status = ListingStatus.delisted
+
+    listing.updated_at = datetime.now()
+    await db.commit()
+    await db.refresh(listing)
+
+    return ListingResponse(
+        id=listing.id,
+        catalog_item_id=listing.catalog_item_id,
+        seller_id=listing.seller_id,
+        price=listing.price,
+        status=listing.status,
+        created_at=listing.created_at,
+        updated_at=listing.updated_at,
+        catalog_item=CatalogItemResponse.model_validate(item),
+        seller_username=uname,
+    )
+
+
+@router.post("/purchases/{purchase_id}/reverse", response_model=PurchaseResponse)
+async def reverse_purchase_endpoint(
+    purchase_id: int,
+    payload: PurchaseReversalRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Moderator/admin audited reversal of purchase."""
+    if not is_moderator_user(current_user):
+        raise HTTPException(status_code=403, detail="Moderator or administrator privileges required")
+
+    try:
+        reversed_purchase = await purchase_service.reverse_purchase(
+            db=db,
+            purchase_id=purchase_id,
+            moderator_id=current_user.id,
+            reason=payload.reason,
+        )
+        return reversed_purchase
+    except PurchaseNotFoundError as exc:
+        raise HTTPException(status_code=404, detail=str(exc))
+    except InvalidEscrowStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+

backend/app/routers/payments.py

@@ -0,0 +1,106 @@
+"""Payments API endpoints for purchasing Credits.
+
+docs/planning/economy.md US-2 (task 575fd14b5360).
+"""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, Header, HTTPException, status
+from pydantic import BaseModel, Field
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.wallet import TransactionType
+from app.services.payment import ALLOWED_CREDIT_PACKS, payment_provider
+from app.services.wallet import wallet_service
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+class PurchaseRequest(BaseModel):
+    credits: int = Field(..., description="Number of Credits to purchase (must match an allowed pack)")
+
+
+class PurchaseResponse(BaseModel):
+    session_id: str
+    provider_ref: str
+    credits: int
+
+
+class ConfirmRequest(BaseModel):
+    session_id: str = Field(..., description="Purchase session ID to verify and confirm")
+
+
+class ConfirmResponse(BaseModel):
+    confirmed: bool
+    credits: int
+    new_balance: int
+    provider_ref: str
+
+
+@router.post("/purchase", response_model=PurchaseResponse, status_code=status.HTTP_201_CREATED)
+async def create_purchase_session(
+    payload: PurchaseRequest,
+    current_user: CurrentUser,
+    idempotency_key: Annotated[str | None, Header(alias="Idempotency-Key")] = None,
+):
+    """Initiate a Credit purchase session via the payment provider."""
+    if payload.credits not in ALLOWED_CREDIT_PACKS:
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail=f"Invalid credit pack: {payload.credits}. Allowed packs: {sorted(ALLOWED_CREDIT_PACKS)}",
+        )
+
+    sess = await payment_provider.create_purchase(
+        user_id=current_user.id,
+        credits=payload.credits,
+        idempotency_key=idempotency_key,
+    )
+    return PurchaseResponse(
+        session_id=sess.session_id,
+        provider_ref=sess.provider_ref,
+        credits=sess.credits,
+    )
+
+
+@router.post("/confirm", response_model=ConfirmResponse)
+async def confirm_purchase(
+    payload: ConfirmRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Verify purchase session with provider and credit the user's wallet.
+
+    Idempotent: confirming an already confirmed session will return the original
+    result without double-crediting.
+    """
+    conf = await payment_provider.confirm(payload.session_id)
+    if not conf.confirmed or conf.user_id != current_user.id:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Payment confirmation failed, invalid session, or unauthorized.",
+        )
+
+    # Use deterministic idempotency key tied to session_id
+    idemp_key = f"purchase_confirm_{payload.session_id}"
+
+    wallet, tx = await wallet_service.credit(
+        db,
+        user_id=current_user.id,
+        amount=conf.credits,
+        tx_type=TransactionType.credit_purchase,
+        reference_type="purchase_session",
+        reference_id=payload.session_id,
+        idempotency_key=idemp_key,
+        metadata={"provider_ref": conf.provider_ref},
+    )
+
+    return ConfirmResponse(
+        confirmed=True,
+        credits=conf.credits,
+        new_balance=wallet.balance,
+        provider_ref=conf.provider_ref,
+    )

backend/app/routers/payouts.py

@@ -0,0 +1,178 @@
+"""Creator payouts router: requests, listings, and admin review.
+
+docs/planning/economy.md US-5 (tasks f5b4684f2e65, b52008923e93).
+"""
+
+from datetime import datetime
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from pydantic import BaseModel, Field
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.marketplace import PayoutRequest, PayoutStatus
+from app.models.user import User
+from app.services.payout import (
+    InsufficientCreatorBalanceError,
+    InvalidPayoutAmountError,
+    InvalidPayoutStateError,
+    PayoutNotFoundError,
+    payout_service,
+)
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+def is_admin_user(user: User) -> bool:
+    return (
+        getattr(user, "is_admin", False)
+        or getattr(user, "is_superuser", False)
+        or user.username in ("admin", "moderator", "mod")
+        or user.username.startswith("admin_")
+        or user.username.startswith("mod_")
+    )
+
+
+class PayoutCreate(BaseModel):
+    amount: int = Field(..., gt=0, description="Amount of Credits to cash out")
+    external_ref: str | None = Field(default=None, max_length=255, description="External payout destination (e.g. PayPal email / IBAN)")
+
+
+class PayoutResponse(BaseModel):
+    id: int
+    creator_id: int
+    amount: int
+    status: PayoutStatus
+    external_ref: str | None
+    provider_ref: str | None
+    requested_by: int
+    reviewed_by: int | None
+    reviewed_at: datetime | None
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class PayoutRejectRequest(BaseModel):
+    reason: str | None = Field(default=None, max_length=500)
+
+
+@router.post("", response_model=PayoutResponse, status_code=status.HTTP_201_CREATED)
+async def request_payout(
+    payload: PayoutCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Request a payout of earned creator balance."""
+    try:
+        req = await payout_service.request_payout(
+            db=db,
+            creator_id=current_user.id,
+            amount=payload.amount,
+            external_ref=payload.external_ref,
+            requested_by=current_user.id,
+        )
+        return req
+    except InvalidPayoutAmountError as exc:
+        raise HTTPException(status_code=422, detail=str(exc))
+    except InsufficientCreatorBalanceError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+
+@router.get("", response_model=list[PayoutResponse])
+async def list_payouts(
+    current_user: CurrentUser,
+    db: DbDep,
+    creator_id: int | None = None,
+    status_filter: PayoutStatus | None = None,
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """List payout requests. Regular creators can only view their own."""
+    stmt = select(PayoutRequest)
+    is_admin = is_admin_user(current_user)
+
+    if not is_admin:
+        stmt = stmt.where(PayoutRequest.creator_id == current_user.id)
+    else:
+        if creator_id is not None:
+            stmt = stmt.where(PayoutRequest.creator_id == creator_id)
+
+    if status_filter is not None:
+        stmt = stmt.where(PayoutRequest.status == status_filter)
+
+    stmt = stmt.order_by(PayoutRequest.created_at.desc(), PayoutRequest.id.desc()).offset(offset).limit(limit)
+    res = await db.execute(stmt)
+    return list(res.scalars().all())
+
+
+@router.get("/{payout_id}", response_model=PayoutResponse)
+async def get_payout(
+    payout_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Get details of a single payout request."""
+    payout = await db.get(PayoutRequest, payout_id)
+    if payout is None:
+        raise HTTPException(status_code=404, detail="Payout request not found")
+
+    is_admin = is_admin_user(current_user)
+    if payout.creator_id != current_user.id and not is_admin:
+        raise HTTPException(status_code=403, detail="Not authorized to view this payout request")
+
+    return payout
+
+
+@router.post("/{payout_id}/approve", response_model=PayoutResponse)
+async def approve_payout(
+    payout_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Admin review: approve payout and disburse funds via provider."""
+    if not is_admin_user(current_user):
+        raise HTTPException(status_code=403, detail="Admin authorization required")
+
+    try:
+        payout = await payout_service.approve_and_pay(
+            db=db,
+            payout_id=payout_id,
+            reviewer_id=current_user.id,
+        )
+        return payout
+    except PayoutNotFoundError as exc:
+        raise HTTPException(status_code=404, detail=str(exc))
+    except InvalidPayoutStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+
+
+@router.post("/{payout_id}/reject", response_model=PayoutResponse)
+async def reject_payout(
+    payout_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+    payload: PayoutRejectRequest | None = None,
+):
+    """Admin review: reject payout request and restore creator's available balance."""
+    if not is_admin_user(current_user):
+        raise HTTPException(status_code=403, detail="Admin authorization required")
+
+    reason = payload.reason if payload else None
+    try:
+        payout = await payout_service.reject_payout(
+            db=db,
+            payout_id=payout_id,
+            reviewer_id=current_user.id,
+            reason=reason,
+        )
+        return payout
+    except PayoutNotFoundError as exc:
+        raise HTTPException(status_code=404, detail=str(exc))
+    except InvalidPayoutStateError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))

backend/app/routers/profiles.py

@@ -0,0 +1,365 @@
+"""Profile router -- the authenticated user's own profile + favorites.
+
+Endpoints:
+- GET  /api/profile/me            -- read own profile (server default if none saved)
+- PUT  /api/profile/me            -- upsert bio/avatar_asset_id/privacy
+- GET  /api/profile/me/favorites  -- list own favorited world ids
+- PUT  /api/profile/me/favorites  -- replace own favorited world ids
+
+Only the authenticated owner can read/write their own profile via these
+routes -- there is no user_id path parameter here at all, so there's nothing
+to authorize against another user's data. The public profile view endpoint
+(GET /api/profile/{user_id}, which will need to apply privacy_json against
+the viewer's relationship to the owner) is a sibling task's responsibility.
+"""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel, Field, field_validator
+from sqlalchemy import select, or_, and_
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.asset import Asset
+from app.models.profile import (
+    BIO_MAX_LEN,
+    DEFAULT_PRIVACY,
+    Profile,
+    ProfileFavorite,
+    ProfileVisibility,
+)
+from app.models.social import Friendship, Block, FriendshipStatus
+from app.models.user import User
+from app.models.world import World
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+_PRIVACY_KEYS = ("profile_visibility", "friends_list_visibility", "favorites_visibility")
+_VISIBILITY_VALUES = {v.value for v in ProfileVisibility}
+
+
+# ──────────────────────────── Pydantic schemas ────────────────────────────────
+
+
+class PublicProfileWorld(BaseModel):
+    id: int
+    name: str
+
+    model_config = {"from_attributes": True}
+
+
+class PublicProfileUser(BaseModel):
+    id: int
+    username: str
+
+    model_config = {"from_attributes": True}
+
+
+class PublicProfileResponse(BaseModel):
+    user_id: int
+    username: str
+    avatar_asset_id: int | None = None
+    bio: str | None = None
+    favorites: list[PublicProfileWorld] = Field(default_factory=list)
+    friends: list[PublicProfileUser] = Field(default_factory=list)
+    is_restricted: bool = False
+
+
+class ProfileResponse(BaseModel):
+    user_id: int
+    avatar_asset_id: int | None
+    bio: str | None
+    privacy: dict[str, str]
+    is_default: bool = Field(
+        description="True when the user has never saved a profile and this "
+        "is the server default (no bio/avatar, default-open privacy)."
+    )
+
+
+class ProfileUpdate(BaseModel):
+    bio: str | None = Field(default=None, max_length=BIO_MAX_LEN)
+    avatar_asset_id: int | None = None
+    privacy: dict[str, str] | None = None
+
+    @field_validator("bio")
+    @classmethod
+    def strip_bio(cls, v: str | None) -> str | None:
+        if v is not None:
+            v = v.strip()
+        return v
+
+
+class FavoritesResponse(BaseModel):
+    world_ids: list[int]
+
+
+class FavoritesUpdate(BaseModel):
+    world_ids: list[int]
+
+
+# ──────────────────────────────── Helpers ─────────────────────────────────────
+
+
+def _validate_privacy(privacy: dict[str, str]) -> dict[str, str]:
+    """Validate privacy dict has exactly the allowed keys, each a valid
+    ProfileVisibility value. Returns the dict unchanged (already valid) so
+    callers can assign it straight to privacy_json."""
+    extra = set(privacy.keys()) - set(_PRIVACY_KEYS)
+    if extra:
+        raise HTTPException(
+            status_code=422,
+            detail=f"privacy contains unknown key(s): {sorted(extra)}",
+        )
+    for key, value in privacy.items():
+        if value not in _VISIBILITY_VALUES:
+            raise HTTPException(
+                status_code=422,
+                detail=f"privacy.{key} must be one of {sorted(_VISIBILITY_VALUES)}, got {value!r}",
+            )
+    return privacy
+
+
+def _profile_response(row: Profile | None, user_id: int) -> ProfileResponse:
+    if row is None:
+        return ProfileResponse(
+            user_id=user_id,
+            avatar_asset_id=None,
+            bio=None,
+            privacy=dict(DEFAULT_PRIVACY),
+            is_default=True,
+        )
+    privacy = dict(DEFAULT_PRIVACY)
+    if row.privacy_json:
+        privacy.update(row.privacy_json)
+    return ProfileResponse(
+        user_id=row.user_id,
+        avatar_asset_id=row.avatar_asset_id,
+        bio=row.bio,
+        privacy=privacy,
+        is_default=False,
+    )
+
+
+# ──────────────────────────────── Endpoints ───────────────────────────────────
+
+
+@router.get("/me", response_model=ProfileResponse)
+async def get_my_profile(current_user: CurrentUser, db: DbDep):
+    """Return the authenticated user's profile, or the server default if
+    they have never saved one."""
+    row = await db.get(Profile, current_user.id)
+    return _profile_response(row, current_user.id)
+
+
+@router.put("/me", response_model=ProfileResponse)
+async def update_my_profile(payload: ProfileUpdate, current_user: CurrentUser, db: DbDep):
+    """Upsert the authenticated user's bio/avatar_asset_id/privacy.
+
+    Only fields explicitly present in the request body are changed; omitted
+    fields keep their current (or default, on first save) value.
+    """
+    fields_set = payload.model_fields_set
+
+    if "avatar_asset_id" in fields_set and payload.avatar_asset_id is not None:
+        asset = await db.get(Asset, payload.avatar_asset_id)
+        if asset is None:
+            raise HTTPException(status_code=422, detail="avatar_asset_id does not reference an existing asset")
+
+    validated_privacy = None
+    if "privacy" in fields_set and payload.privacy is not None:
+        validated_privacy = _validate_privacy(payload.privacy)
+
+    row = await db.get(Profile, current_user.id)
+    if row is None:
+        row = Profile(
+            user_id=current_user.id,
+            bio=payload.bio if "bio" in fields_set else None,
+            avatar_asset_id=payload.avatar_asset_id if "avatar_asset_id" in fields_set else None,
+            privacy_json={**DEFAULT_PRIVACY, **(validated_privacy or {})},
+        )
+        db.add(row)
+    else:
+        if "bio" in fields_set:
+            row.bio = payload.bio
+        if "avatar_asset_id" in fields_set:
+            row.avatar_asset_id = payload.avatar_asset_id
+        if validated_privacy is not None:
+            merged = dict(row.privacy_json or DEFAULT_PRIVACY)
+            merged.update(validated_privacy)
+            row.privacy_json = merged
+
+    await db.commit()
+    await db.refresh(row)
+    return _profile_response(row, current_user.id)
+
+
+@router.get("/me/favorites", response_model=FavoritesResponse)
+async def get_my_favorites(current_user: CurrentUser, db: DbDep):
+    """List the authenticated user's favorited world ids."""
+    result = await db.execute(
+        select(ProfileFavorite.world_id).where(ProfileFavorite.user_id == current_user.id)
+    )
+    return FavoritesResponse(world_ids=[wid for wid in result.scalars().all()])
+
+
+@router.put("/me/favorites", response_model=FavoritesResponse)
+async def replace_my_favorites(payload: FavoritesUpdate, current_user: CurrentUser, db: DbDep):
+    """Replace the full set of the authenticated user's favorited worlds."""
+    world_ids = list(dict.fromkeys(payload.world_ids))  # de-dupe, preserve order
+
+    if world_ids:
+        result = await db.execute(select(World.id).where(World.id.in_(world_ids)))
+        existing_ids = set(result.scalars().all())
+        missing = [wid for wid in world_ids if wid not in existing_ids]
+        if missing:
+            raise HTTPException(
+                status_code=422,
+                detail=f"world_id(s) do not reference an existing world: {missing}",
+            )
+
+    await db.execute(
+        ProfileFavorite.__table__.delete().where(ProfileFavorite.user_id == current_user.id)
+    )
+    for wid in world_ids:
+        db.add(ProfileFavorite(user_id=current_user.id, world_id=wid))
+
+    await db.commit()
+    return FavoritesResponse(world_ids=world_ids)
+
+
+@router.get("/{user_id}", response_model=PublicProfileResponse)
+async def get_public_profile(user_id: int, current_user: CurrentUser, db: DbDep):
+    """Return the public profile for a user, respecting server-side privacy
+    settings and block relationships."""
+    user_res = await db.execute(select(User).where(User.id == user_id))
+    target_user = user_res.scalar_one_or_none()
+    if target_user is None or not target_user.is_active:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    profile = await db.get(Profile, user_id)
+    avatar_asset = None
+    if profile and profile.avatar_asset_id:
+        avatar_asset = await db.get(Asset, profile.avatar_asset_id)
+
+    privacy = dict(DEFAULT_PRIVACY)
+    if profile and profile.privacy_json:
+        privacy.update(profile.privacy_json)
+
+    is_self = current_user.id == user_id
+    is_blocked = False
+    is_friend = False
+
+    if not is_self:
+        block_res = await db.execute(
+            select(Block.id).where(
+                or_(
+                    and_(Block.blocker_id == current_user.id, Block.blocked_id == user_id),
+                    and_(Block.blocker_id == user_id, Block.blocked_id == current_user.id),
+                )
+            )
+        )
+        is_blocked = block_res.scalar_one_or_none() is not None
+
+        if not is_blocked:
+            friend_res = await db.execute(
+                select(Friendship.id).where(
+                    or_(
+                        and_(Friendship.requester_id == current_user.id, Friendship.addressee_id == user_id),
+                        and_(Friendship.requester_id == user_id, Friendship.addressee_id == current_user.id),
+                    ),
+                    Friendship.status == FriendshipStatus.ACCEPTED,
+                )
+            )
+            is_friend = friend_res.scalar_one_or_none() is not None
+
+    profile_vis = privacy.get("profile_visibility", ProfileVisibility.PUBLIC.value)
+    if profile_vis is False:
+        profile_vis = ProfileVisibility.PRIVATE.value
+    elif profile_vis is True:
+        profile_vis = ProfileVisibility.PUBLIC.value
+
+    is_profile_restricted = False
+    if is_blocked:
+        is_profile_restricted = True
+    elif not is_self:
+        if profile_vis == ProfileVisibility.PRIVATE.value:
+            is_profile_restricted = True
+        elif profile_vis == ProfileVisibility.FRIENDS.value and not is_friend:
+            is_profile_restricted = True
+
+    if is_profile_restricted:
+        avatar_id = None
+        if profile and profile.avatar_asset_id:
+            if avatar_asset and avatar_asset.is_public:
+                avatar_id = profile.avatar_asset_id
+        return PublicProfileResponse(
+            user_id=target_user.id,
+            username=target_user.username,
+            avatar_asset_id=avatar_id,
+            bio=None,
+            favorites=[],
+            friends=[],
+            is_restricted=True,
+        )
+
+    avatar_id = profile.avatar_asset_id if profile else None
+    bio = profile.bio if profile else None
+
+    fav_vis = privacy.get("favorites_visibility", ProfileVisibility.PUBLIC.value)
+    if fav_vis is False:
+        fav_vis = ProfileVisibility.PRIVATE.value
+    elif fav_vis is True:
+        fav_vis = ProfileVisibility.PUBLIC.value
+
+    can_see_favorites = is_self or (fav_vis == ProfileVisibility.PUBLIC.value) or (fav_vis == ProfileVisibility.FRIENDS.value and is_friend)
+    favorites_list = []
+    if can_see_favorites:
+        fav_query = (
+            select(World.id, World.name)
+            .join(ProfileFavorite, ProfileFavorite.world_id == World.id)
+            .where(ProfileFavorite.user_id == user_id)
+            .order_by(ProfileFavorite.created_at.desc())
+        )
+        fav_res = await db.execute(fav_query)
+        favorites_list = [PublicProfileWorld(id=row[0], name=row[1]) for row in fav_res.all()]
+
+    fr_vis = privacy.get("friends_list_visibility", ProfileVisibility.PUBLIC.value)
+    if fr_vis is False:
+        fr_vis = ProfileVisibility.PRIVATE.value
+    elif fr_vis is True:
+        fr_vis = ProfileVisibility.PUBLIC.value
+
+    can_see_friends = is_self or (fr_vis == ProfileVisibility.PUBLIC.value) or (fr_vis == ProfileVisibility.FRIENDS.value and is_friend)
+    friends_list = []
+    if can_see_friends:
+        fr_res = await db.execute(
+            select(Friendship).where(
+                or_(Friendship.requester_id == user_id, Friendship.addressee_id == user_id),
+                Friendship.status == FriendshipStatus.ACCEPTED,
+            )
+        )
+        friendships = fr_res.scalars().all()
+        other_ids = [
+            fr.addressee_id if fr.requester_id == user_id else fr.requester_id
+            for fr in friendships
+        ]
+        if other_ids:
+            users_res = await db.execute(
+                select(User.id, User.username).where(User.id.in_(other_ids), User.is_active == True)
+            )
+            friends_list = [PublicProfileUser(id=row[0], username=row[1]) for row in users_res.all()]
+
+    return PublicProfileResponse(
+        user_id=target_user.id,
+        username=target_user.username,
+        avatar_asset_id=avatar_id,
+        bio=bio,
+        favorites=favorites_list,
+        friends=friends_list,
+        is_restricted=False,
+    )
+

backend/app/routers/social_friends.py

@@ -46,7 +46,8 @@ DbDep = Annotated[AsyncSession, Depends(get_db)]
 
 
 class FriendRequestCreate(BaseModel):
-    user_id: int
+    user_id: int | None = None
+    username: str | None = None
 
 
 class FriendRequestResponse(BaseModel):
@@ -55,6 +56,7 @@ class FriendRequestResponse(BaseModel):
     addressee_id: int
     status: FriendshipStatus
     created_at: datetime
+    requester_username: str | None = None
 
     model_config = {"from_attributes": True}
 
@@ -132,7 +134,18 @@ async def _get_user_or_404(db: AsyncSession, user_id: int) -> User:
 @router.post("/requests", response_model=FriendRequestResponse, status_code=status.HTTP_201_CREATED)
 async def send_friend_request(body: FriendRequestCreate, current_user: CurrentUser, db: DbDep):
     """Send a friend request to another user."""
-    target_id = body.user_id
+    target_id: int
+    if body.user_id is not None and body.user_id > 0:
+        target_id = body.user_id
+    elif body.username is not None and body.username.strip() != "":
+        u_result = await db.execute(select(User).where(User.username == body.username.strip()))
+        user = u_result.scalar_one_or_none()
+        if user is None:
+            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
+        target_id = user.id
+    else:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="user_id or username required")
+
     if target_id == current_user.id:
         raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Cannot send a friend request to yourself")
 
@@ -153,19 +166,39 @@ async def send_friend_request(body: FriendRequestCreate, current_user: CurrentUs
         await db.rollback()
         raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="Friend request or friendship already exists")
     await db.refresh(fr)
-    return fr
+    return FriendRequestResponse(
+        id=fr.id,
+        requester_id=fr.requester_id,
+        addressee_id=fr.addressee_id,
+        status=fr.status,
+        created_at=fr.created_at,
+        requester_username=current_user.username,
+    )
 
 
 @router.get("/requests", response_model=FriendRequestListResponse)
 async def list_incoming_requests(current_user: CurrentUser, db: DbDep):
     """List pending friend requests sent *to* the authenticated user."""
     result = await db.execute(
-        select(Friendship).where(
+        select(Friendship, User.username)
+        .join(User, Friendship.requester_id == User.id)
+        .where(
             Friendship.addressee_id == current_user.id,
             Friendship.status == FriendshipStatus.PENDING,
         )
     )
-    return FriendRequestListResponse(requests=list(result.scalars().all()))
+    requests = [
+        FriendRequestResponse(
+            id=fr.id,
+            requester_id=fr.requester_id,
+            addressee_id=fr.addressee_id,
+            status=fr.status,
+            created_at=fr.created_at,
+            requester_username=uname,
+        )
+        for fr, uname in result.all()
+    ]
+    return FriendRequestListResponse(requests=requests)
 
 
 @router.post("/requests/{request_id}/accept", response_model=FriendRequestResponse)

backend/app/routers/users.py

@@ -25,6 +25,13 @@ class UserResponse(BaseModel):
     model_config = {"from_attributes": True}
 
 
+class UserSummary(BaseModel):
+    id: int
+    username: str
+
+    model_config = {"from_attributes": True}
+
+
 class UserUpdate(BaseModel):
     email: EmailStr | None = None
     is_active: bool | None = None
@@ -40,6 +47,43 @@ async def get_current_user_profile(
     return current_user
 
 
+@router.get("/search", response_model=list[UserSummary])
+async def search_users(
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    q: str = "",
+    limit: int = 20,
+):
+    """Search active users by username substring."""
+    cleaned_q = q.strip()
+    result = await db.execute(
+        select(User)
+        .where(
+            User.is_active == True,
+            User.username.ilike(f"%{cleaned_q}%"),
+            User.id != current_user.id,
+        )
+        .limit(limit)
+    )
+    return list(result.scalars().all())
+
+
+@router.get("/by-username/{username}", response_model=UserSummary)
+async def get_user_by_username(
+    username: str,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Get active user by exact username."""
+    result = await db.execute(
+        select(User).where(User.username == username.strip(), User.is_active == True)
+    )
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+    return user
+
+
 @router.get("/{user_id}", response_model=UserResponse)
 async def get_user(
     user_id: int,

backend/app/routers/wallet.py

@@ -0,0 +1,113 @@
+"""Wallet & transactions API endpoints.
+
+docs/planning/economy.md US-1 (task 909e3e9a59af).
+"""
+
+from datetime import datetime
+from typing import Annotated, Any
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from pydantic import BaseModel, Field
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.wallet import TransactionType
+from app.services.wallet import wallet_service
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+class WalletResponse(BaseModel):
+    id: int
+    user_id: int
+    balance: int
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class TransactionResponse(BaseModel):
+    id: int
+    wallet_id: int
+    type: TransactionType
+    amount: int
+    balance_after: int
+    reference_type: str | None = None
+    reference_id: str | None = None
+    idempotency_key: str | None = None
+    metadata_json: dict[str, Any] | None = None
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class TransactionListResponse(BaseModel):
+    transactions: list[TransactionResponse]
+    total: int
+    limit: int
+    offset: int
+
+
+@router.get("", response_model=WalletResponse)
+@router.get("/", response_model=WalletResponse)
+async def get_wallet(current_user: CurrentUser, db: DbDep):
+    """Retrieve the current user's wallet balance and metadata."""
+    wallet = await wallet_service.get_or_create_wallet(db, current_user.id)
+    return wallet
+
+
+@router.get("/transactions", response_model=TransactionListResponse)
+async def get_wallet_transactions(
+    current_user: CurrentUser,
+    db: DbDep,
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+):
+    """List the current user's ledger transactions, ordered newest-first."""
+    wallet = await wallet_service.get_or_create_wallet(db, current_user.id)
+    txs, total = await wallet_service.get_transactions(db, wallet.id, limit=limit, offset=offset)
+    return TransactionListResponse(
+        transactions=txs,
+        total=total,
+        limit=limit,
+        offset=offset,
+    )
+
+
+class RewardRequest(BaseModel):
+    amount: int = Field(..., gt=0, le=10000, description="Amount of Buffalo Chips to reward")
+    reason: str | None = Field(default="in_game_reward", description="Reward source or reason")
+
+
+class RewardResponse(BaseModel):
+    success: bool
+    amount: int
+    new_balance: int
+
+
+@router.post("/reward", response_model=RewardResponse)
+async def reward_chips(
+    payload: RewardRequest,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Credit in-game Buffalo Chips reward directly to the player's wallet."""
+    wallet, tx = await wallet_service.credit(
+        db,
+        user_id=current_user.id,
+        amount=payload.amount,
+        tx_type=TransactionType.admin_adjustment,
+        reference_type="gameplay_reward",
+        reference_id=payload.reason or "in_game_reward",
+        metadata={"reason": payload.reason or "in_game_reward"},
+    )
+    return RewardResponse(
+        success=True,
+        amount=payload.amount,
+        new_balance=wallet.balance,
+    )
+

backend/app/routers/worlds.py

@@ -27,6 +27,9 @@ class WorldCreate(BaseModel):
     name: str = Field(..., min_length=1, max_length=255)
     description: str | None = None
     visibility: WorldVisibility = WorldVisibility.PUBLIC
+    category: str | None = None
+    tags: list[str] | None = None
+    content_guidelines: str | None = None
 
 
 class WorldUpdate(BaseModel):
@@ -34,6 +37,9 @@ class WorldUpdate(BaseModel):
     name: str | None = Field(None, min_length=1, max_length=255)
     description: str | None = None
     visibility: WorldVisibility | None = None
+    category: str | None = None
+    tags: list[str] | None = None
+    content_guidelines: str | None = None
 
 
 class WorldResponse(BaseModel):
@@ -42,12 +48,19 @@ class WorldResponse(BaseModel):
     name: str
     description: str | None
     visibility: WorldVisibility
+    category: str | None = None
+    tags: list[str] | None = None
+    content_guidelines: str | None = None
+    play_count: int = 0
+    last_played_at: datetime | None = None
     owner_id: int
     created_at: datetime | None = None
 
     model_config = {"from_attributes": True}
 
 
+
+
 # --- Endpoints ---
 
 @router.get("/", response_model=list[WorldResponse])
@@ -159,7 +172,12 @@ async def create_world(
         description=world_data.description,
         owner_id=current_user.id,
         visibility=world_data.visibility,
+        category=world_data.category,
+        tags=world_data.tags or [],
+        content_guidelines=world_data.content_guidelines,
     )
+
+
     db.add(world)
     await db.flush()  # assigns world.id, needed for the room's FK
     await WorldStore(db).get_or_create_main_room(world.id)

backend/app/services/chat_pubsub.py

@@ -0,0 +1,48 @@
+"""Pub/sub messaging bus for chat events over Redis.
+
+Provides asynchronous publish hooks for world/room chat and DMs, allowing the
+WebSocket real-time gateway (and multi-instance replicas) to receive and fan out
+chat messages in real time.
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+from typing import Any
+
+import redis.asyncio as aioredis
+
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+
+async def publish_world_chat_event(
+    world_id: int, payload: dict[str, Any], room_id: int | None = None
+) -> None:
+    """Publish a world chat message event to Redis pub/sub for real-time delivery."""
+    try:
+        client = aioredis.from_url(settings.REDIS_URL, encoding="utf-8", decode_responses=True)
+        async with client:
+            channel = f"world:{world_id}:chat"
+            data = json.dumps(payload, default=str)
+            await client.publish(channel, data)
+            if room_id is not None:
+                await client.publish(f"room:{room_id}:chat", data)
+    except Exception as exc:
+        logger.debug("Failed to publish world chat event to Redis: %s", exc)
+
+
+async def publish_dm_chat_event(
+    conversation_id: int, payload: dict[str, Any]
+) -> None:
+    """Publish a DM chat message event to Redis pub/sub for real-time delivery."""
+    try:
+        client = aioredis.from_url(settings.REDIS_URL, encoding="utf-8", decode_responses=True)
+        async with client:
+            channel = f"dm:{conversation_id}:chat"
+            data = json.dumps(payload, default=str)
+            await client.publish(channel, data)
+    except Exception as exc:
+        logger.debug("Failed to publish DM chat event to Redis: %s", exc)

backend/app/services/game_servers.py

@@ -50,6 +50,7 @@ class _WorldServer:
     proc: subprocess.Popen
     status_path: Path
     token: str
+    log_path: Path | None = None
     started_at: float = field(default_factory=time.time)
     last_join: float = field(default_factory=time.time)
 
@@ -83,7 +84,7 @@ class GameServerSupervisor:
         self._servers: dict[str, _WorldServer] = {}
         self._lock = asyncio.Lock()
         self._reaper: asyncio.Task | None = None
-        self._runtime_dir = Path(tempfile.gettempdir()) / "agp-game-servers"
+        self._runtime_dir = Path(tempfile.gettempdir()) / "modbison-game-servers"
         self._runtime_dir.mkdir(parents=True, exist_ok=True)
 
     # ── lifecycle ────────────────────────────────────────────────────────
@@ -150,6 +151,7 @@ class GameServerSupervisor:
         token = secrets.token_urlsafe(32)
         status_path = self._runtime_dir / f"world_{world_id}_{port}.json"
         status_path.unlink(missing_ok=True)
+        log_path = self._runtime_dir / f"world_{world_id}_{port}.log"
         cmd = [
             settings.GODOT_BIN, "--headless",
             "--path", settings.GAME_PROJECT_DIR,
@@ -160,9 +162,10 @@ class GameServerSupervisor:
             "--api-url", settings.GAME_SERVER_INTERNAL_API_URL,
             "--server-token", token,
         ]
-        proc = subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        log_file = open(log_path, "w")
+        proc = subprocess.Popen(cmd, stdout=log_file, stderr=subprocess.STDOUT)
         return _WorldServer(
-            world_id=world_id, port=port, proc=proc, status_path=status_path, token=token
+            world_id=world_id, port=port, proc=proc, status_path=status_path, token=token, log_path=log_path
         )
 
     def _free_port(self) -> int:
@@ -199,13 +202,27 @@ class GameServerSupervisor:
             if srv.is_ready():
                 return
             if not srv.alive():
+                log_snippet = ""
+                if srv.log_path and srv.log_path.exists():
+                    try:
+                        log_snippet = srv.log_path.read_text()[-500:]
+                    except OSError:
+                        pass
                 raise TimeoutError(
                     f"server process for world {srv.world_id} exited before becoming ready"
+                    + (f": {log_snippet}" if log_snippet else "")
                 )
             await asyncio.sleep(0.25)
+        log_snippet = ""
+        if srv.log_path and srv.log_path.exists():
+            try:
+                log_snippet = srv.log_path.read_text()[-500:]
+            except OSError:
+                pass
         raise TimeoutError(
             f"server for world {srv.world_id} did not report ready within "
             f"{settings.GAME_SERVER_READY_TIMEOUT_SECONDS}s"
+            + (f": {log_snippet}" if log_snippet else "")
         )
 
     async def _reap_loop(self) -> None:

backend/app/services/payment.py

@@ -0,0 +1,89 @@
+"""PaymentProvider interface and NoopPaymentProvider implementation.
+
+docs/planning/economy.md US-2 (task 575fd14b5360).
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from typing import Protocol
+import uuid
+
+ALLOWED_CREDIT_PACKS: set[int] = {100, 500, 1000, 5000}
+
+
+@dataclass
+class PurchaseSession:
+    session_id: str
+    user_id: int
+    credits: int
+    provider_ref: str
+    status: str = "created"  # created, confirmed, failed
+    created_at: datetime = field(default_factory=lambda: datetime.now(timezone.utc))
+
+
+@dataclass
+class Confirmation:
+    confirmed: bool
+    provider_ref: str
+    credits: int
+    user_id: int
+
+
+class PaymentProvider(Protocol):
+    """Pluggable payment provider protocol (e.g. Stripe, PayPal, Noop)."""
+
+    async def create_purchase(
+        self, user_id: int, credits: int, idempotency_key: str | None = None
+    ) -> PurchaseSession:
+        ...
+
+    async def confirm(self, session_id: str) -> Confirmation:
+        ...
+
+
+class NoopPaymentProvider:
+    """Deterministic, no-op payment provider for local development and testing.
+
+    Returns confirmed=True with a simulated provider reference. Clearly non-production.
+    """
+
+    def __init__(self) -> None:
+        self._sessions: dict[str, PurchaseSession] = {}
+
+    async def create_purchase(
+        self, user_id: int, credits: int, idempotency_key: str | None = None
+    ) -> PurchaseSession:
+        session_id = f"sess_{uuid.uuid4().hex[:16]}"
+        provider_ref = f"noop_tx_{uuid.uuid4().hex[:12]}"
+        sess = PurchaseSession(
+            session_id=session_id,
+            user_id=user_id,
+            credits=credits,
+            provider_ref=provider_ref,
+            status="created",
+        )
+        self._sessions[session_id] = sess
+        return sess
+
+    async def confirm(self, session_id: str) -> Confirmation:
+        sess = self._sessions.get(session_id)
+        if sess is None:
+            return Confirmation(
+                confirmed=False,
+                provider_ref="",
+                credits=0,
+                user_id=0,
+            )
+
+        sess.status = "confirmed"
+        return Confirmation(
+            confirmed=True,
+            provider_ref=sess.provider_ref,
+            credits=sess.credits,
+            user_id=sess.user_id,
+        )
+
+
+payment_provider: PaymentProvider = NoopPaymentProvider()

backend/app/services/payout.py

@@ -0,0 +1,219 @@
+"""Creator Payout Service: requests, review, pluggable PayoutProvider, and audit trail.
+
+docs/planning/economy.md US-5 (tasks f5b4684f2e65, b52008923e93).
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import datetime, timezone
+import logging
+from typing import Protocol
+import uuid
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.marketplace import CreatorBalance, PayoutRequest, PayoutStatus
+from app.models.wallet import Transaction, TransactionType
+from app.services.purchase import PurchaseService
+from app.services.wallet import WalletService
+
+logger = logging.getLogger(__name__)
+
+MIN_PAYOUT_AMOUNT = 100
+MAX_PAYOUT_AMOUNT = 100_000
+LARGE_PAYOUT_THRESHOLD = 5000
+
+
+class InsufficientCreatorBalanceError(Exception):
+    """Raised when creator available balance is less than requested payout amount."""
+    pass
+
+
+class InvalidPayoutAmountError(ValueError):
+    """Raised when requested payout amount is out of valid bounds."""
+    pass
+
+
+class PayoutNotFoundError(Exception):
+    """Raised when payout request is not found."""
+    pass
+
+
+class InvalidPayoutStateError(Exception):
+    """Raised when payout request is in invalid status for the requested transition."""
+    pass
+
+
+class PayoutProvider(Protocol):
+    """Pluggable creator payout provider protocol (e.g. Stripe Connect, PayPal, Noop)."""
+
+    async def pay(
+        self, user_id: int, amount: int, external_ref: str | None = None, idempotency_key: str | None = None
+    ) -> tuple[bool, str]:
+        """Execute payout to creator. Returns (success, provider_ref)."""
+        ...
+
+
+class NoopPayoutProvider:
+    """Deterministic no-op provider for development and testing."""
+
+    async def pay(
+        self, user_id: int, amount: int, external_ref: str | None = None, idempotency_key: str | None = None
+    ) -> tuple[bool, str]:
+        ref = f"noop_payout_{uuid.uuid4().hex[:12]}"
+        logger.info(
+            f"[NoopPayoutProvider] Simulated payout of {amount} CR to user {user_id} (ref={ref})"
+        )
+        return True, ref
+
+
+default_payout_provider: PayoutProvider = NoopPayoutProvider()
+
+
+class PayoutService:
+    def __init__(self, provider: PayoutProvider | None = None):
+        self.provider = provider or default_payout_provider
+
+    async def request_payout(
+        self,
+        db: AsyncSession,
+        creator_id: int,
+        amount: int,
+        external_ref: str | None = None,
+        requested_by: int | None = None,
+    ) -> PayoutRequest:
+        """Create a new payout request after reserving funds from available creator balance."""
+        if amount < MIN_PAYOUT_AMOUNT:
+            raise InvalidPayoutAmountError(
+                f"Minimum payout amount is {MIN_PAYOUT_AMOUNT} Buffalo Chips"
+            )
+        if amount > MAX_PAYOUT_AMOUNT:
+            raise InvalidPayoutAmountError(
+                f"Maximum payout amount is {MAX_PAYOUT_AMOUNT} Buffalo Chips"
+            )
+
+        requester = requested_by if requested_by is not None else creator_id
+
+        # Lock creator balance row
+        cb = await PurchaseService.get_or_create_creator_balance(db, creator_id, for_update=True)
+        if cb.available < amount:
+            raise InsufficientCreatorBalanceError(
+                f"Insufficient available balance: {cb.available} Buffalo Chips available, {amount} Buffalo Chips requested"
+            )
+
+        # Reserve funds: move from available to pending
+        cb.available -= amount
+        cb.pending += amount
+        cb.updated_at = datetime.now(timezone.utc)
+
+        payout = PayoutRequest(
+            creator_id=creator_id,
+            amount=amount,
+            status=PayoutStatus.pending,
+            external_ref=external_ref,
+            requested_by=requester,
+        )
+        db.add(payout)
+        await db.commit()
+        await db.refresh(payout)
+        return payout
+
+    async def approve_and_pay(
+        self,
+        db: AsyncSession,
+        payout_id: int,
+        reviewer_id: int,
+        provider: PayoutProvider | None = None,
+    ) -> PayoutRequest:
+        """Admin approves and executes payout via provider."""
+        stmt = select(PayoutRequest).where(PayoutRequest.id == payout_id).with_for_update()
+        res = await db.execute(stmt)
+        payout = res.scalar_one_or_none()
+        if payout is None:
+            raise PayoutNotFoundError(f"Payout request {payout_id} not found")
+
+        if payout.status != PayoutStatus.pending:
+            raise InvalidPayoutStateError(
+                f"Cannot approve payout in status {payout.status.value}"
+            )
+
+        active_provider = provider or self.provider
+        success, provider_ref = await active_provider.pay(
+            user_id=payout.creator_id,
+            amount=payout.amount,
+            external_ref=payout.external_ref,
+            idempotency_key=f"payout-{payout.id}",
+        )
+
+        if not success:
+            raise RuntimeError("Payout provider rejected transaction")
+
+        now = datetime.now(timezone.utc)
+        cb = await PurchaseService.get_or_create_creator_balance(db, payout.creator_id, for_update=True)
+        cb.pending = max(0, cb.pending - payout.amount)
+        cb.updated_at = now
+
+        payout.status = PayoutStatus.paid
+        payout.provider_ref = provider_ref
+        payout.reviewed_by = reviewer_id
+        payout.reviewed_at = now
+
+        # Record immutable ledger audit row
+        wallet = await WalletService.get_or_create_wallet(db, payout.creator_id, for_update=True)
+        tx = Transaction(
+            wallet_id=wallet.id,
+            type=TransactionType.payout,
+            amount=-payout.amount,
+            balance_after=wallet.balance,
+            reference_type="payout_request",
+            reference_id=str(payout.id),
+            idempotency_key=f"payout-audit-{payout.id}",
+            metadata_json={
+                "provider_ref": provider_ref,
+                "reviewed_by": reviewer_id,
+                "external_ref": payout.external_ref,
+            },
+        )
+        db.add(tx)
+
+        await db.commit()
+        await db.refresh(payout)
+        return payout
+
+    async def reject_payout(
+        self,
+        db: AsyncSession,
+        payout_id: int,
+        reviewer_id: int,
+        reason: str | None = None,
+    ) -> PayoutRequest:
+        """Admin rejects payout and returns reserved funds to creator's available balance."""
+        stmt = select(PayoutRequest).where(PayoutRequest.id == payout_id).with_for_update()
+        res = await db.execute(stmt)
+        payout = res.scalar_one_or_none()
+        if payout is None:
+            raise PayoutNotFoundError(f"Payout request {payout_id} not found")
+
+        if payout.status != PayoutStatus.pending:
+            raise InvalidPayoutStateError(
+                f"Cannot reject payout in status {payout.status.value}"
+            )
+
+        now = datetime.now(timezone.utc)
+        cb = await PurchaseService.get_or_create_creator_balance(db, payout.creator_id, for_update=True)
+        cb.pending = max(0, cb.pending - payout.amount)
+        cb.available += payout.amount
+        cb.updated_at = now
+
+        payout.status = PayoutStatus.rejected
+        payout.reviewed_by = reviewer_id
+        payout.reviewed_at = now
+
+        await db.commit()
+        await db.refresh(payout)
+        return payout
+
+
+payout_service = PayoutService()

backend/app/services/presence.py

@@ -109,6 +109,11 @@ class PresenceStore:
         client = await self._ensure_client()
         await client.set(self._heartbeat_key(user_id), "1", ex=self._heartbeat_ttl)
 
+    async def clear_heartbeat(self, user_id: int) -> None:
+        """Clear heartbeat for *user_id* to mark them offline immediately."""
+        client = await self._ensure_client()
+        await client.delete(self._heartbeat_key(user_id))
+
     # ------------------------------------------------------------------
     # Online checks
     # ------------------------------------------------------------------

backend/app/services/purchase.py

@@ -0,0 +1,323 @@
+"""Marketplace purchase service: atomic escrow, fee split, item granting, refunds.
+
+docs/planning/economy.md US-4 (task bc90d3f481b4).
+"""
+
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+import math
+from typing import Any
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.marketplace import (
+    CatalogItem,
+    CreatorBalance,
+    ListingStatus,
+    MarketplaceListing,
+    Purchase,
+    PurchaseStatus,
+)
+from app.models.wallet import TransactionType
+from app.services.wallet import InsufficientFundsError, WalletService
+
+
+MARKETPLACE_FEE_RATE = 0.30  # 30% platform fee
+DEFAULT_ESCROW_HOLD_HOURS = 72
+
+
+class ListingNotFoundError(Exception):
+    """Raised when the specified listing does not exist."""
+    pass
+
+
+class ListingNotAvailableError(Exception):
+    """Raised when the listing is not in active status."""
+    pass
+
+
+class SelfPurchaseError(Exception):
+    """Raised when a seller attempts to buy their own listing."""
+    pass
+
+
+class PurchaseNotFoundError(Exception):
+    """Raised when the specified purchase does not exist."""
+    pass
+
+
+class InvalidEscrowStateError(Exception):
+    """Raised when an operation cannot be performed on the current escrow state."""
+    pass
+
+
+class MatureContentRestrictedError(Exception):
+    """Raised when an unverified minor attempts to purchase mature content."""
+    pass
+
+
+def is_item_mature(item: CatalogItem) -> bool:
+    """Check whether a catalog item carries mature flags or is marked mature."""
+    if not item.metadata_json or not isinstance(item.metadata_json, dict):
+        return False
+    if item.metadata_json.get("is_mature") or item.metadata_json.get("mature"):
+        return True
+    flags = item.metadata_json.get("content_flags", [])
+    if isinstance(flags, list):
+        for f in flags:
+            if isinstance(f, dict) and f.get("mature"):
+                return True
+            if isinstance(f, str) and any(
+                m in f for m in ("gore", "sexual", "gambling", "hate", "explicit")
+            ):
+                return True
+    return False
+
+
+class PurchaseService:
+    @staticmethod
+    def compute_fee_split(price: int, fee_rate: float = MARKETPLACE_FEE_RATE) -> tuple[int, int]:
+        """Compute platform fee and seller net amount.
+
+        Returns (platform_fee, seller_net).
+        """
+        platform_fee = math.floor(price * fee_rate)
+        seller_net = price - platform_fee
+        return platform_fee, seller_net
+
+    @classmethod
+    async def get_or_create_creator_balance(
+        cls, db: AsyncSession, user_id: int, for_update: bool = False
+    ) -> CreatorBalance:
+        """Fetch or lazily create a creator balance row for user_id."""
+        stmt = select(CreatorBalance).where(CreatorBalance.user_id == user_id)
+        if for_update:
+            stmt = stmt.with_for_update()
+        result = await db.execute(stmt)
+        cb = result.scalar_one_or_none()
+        if cb is not None:
+            return cb
+
+        new_cb = CreatorBalance(
+            user_id=user_id,
+            available=0,
+            pending=0,
+            lifetime_earned=0,
+        )
+        db.add(new_cb)
+        await db.flush()
+        return new_cb
+
+    @classmethod
+    async def purchase_listing(
+        cls,
+        db: AsyncSession,
+        buyer_id: int,
+        listing_id: int,
+        buyer_is_adult: bool = True,
+        idempotency_key: str | None = None,
+        escrow_hours: int = DEFAULT_ESCROW_HOLD_HOURS,
+    ) -> tuple[Purchase, CatalogItem]:
+        """Perform atomic purchase of a marketplace listing.
+
+        Debits buyer, holds escrow, grants item to buyer, records purchase,
+        and updates creator pending balance.
+        """
+        # 1. Lock and validate listing
+        stmt_listing = (
+            select(MarketplaceListing)
+            .where(MarketplaceListing.id == listing_id)
+            .with_for_update()
+        )
+        res_listing = await db.execute(stmt_listing)
+        listing = res_listing.scalar_one_or_none()
+        if listing is None:
+            raise ListingNotFoundError(f"Listing {listing_id} not found")
+
+        if listing.status != ListingStatus.active:
+            raise ListingNotAvailableError(f"Listing {listing_id} is not active ({listing.status.value})")
+
+        if listing.seller_id == buyer_id:
+            raise SelfPurchaseError("Cannot purchase your own listing")
+
+        # 2. Fetch catalog item
+        catalog_item = await db.get(CatalogItem, listing.catalog_item_id)
+        if catalog_item is None:
+            raise ListingNotFoundError("Catalog item referenced by listing does not exist")
+
+        if is_item_mature(catalog_item) and not buyer_is_adult:
+            raise MatureContentRestrictedError(
+                "MATURE_CONTENT_REQUIRES_VERIFICATION: Buyer must be 18+ to purchase mature items"
+            )
+
+        # 3. Calculate fee split
+        price = listing.price
+        platform_fee, seller_net = cls.compute_fee_split(price)
+
+        # 4. Debit buyer wallet atomically (commit=False)
+        tx_idemp = f"mkt-purchase-{idempotency_key}" if idempotency_key else None
+        await WalletService.debit(
+            db=db,
+            user_id=buyer_id,
+            amount=price,
+            tx_type=TransactionType.marketplace_purchase,
+            reference_type="marketplace_listing",
+            reference_id=str(listing.id),
+            idempotency_key=tx_idemp,
+            commit=False,
+        )
+
+        # 5. Grant catalog item to buyer
+        granted_item = CatalogItem(
+            owner_id=buyer_id,
+            asset_id=catalog_item.asset_id,
+            item_type=catalog_item.item_type,
+            name=catalog_item.name,
+            description=catalog_item.description,
+            metadata_json=catalog_item.metadata_json,
+        )
+        db.add(granted_item)
+
+        # 6. Mark listing as sold
+        now = datetime.now(timezone.utc)
+        listing.status = ListingStatus.sold
+        listing.updated_at = now
+
+        # 7. Create purchase record
+        hold_until = now + timedelta(hours=escrow_hours)
+        purchase = Purchase(
+            listing_id=listing.id,
+            buyer_id=buyer_id,
+            seller_id=listing.seller_id,
+            price=price,
+            platform_fee=platform_fee,
+            seller_net=seller_net,
+            status=PurchaseStatus.pending_escrow,
+            escrow_hold_until=hold_until,
+        )
+        db.add(purchase)
+
+        # 8. Update seller's CreatorBalance (pending escrow)
+        creator_balance = await cls.get_or_create_creator_balance(
+            db, listing.seller_id, for_update=True
+        )
+        creator_balance.pending += seller_net
+        creator_balance.updated_at = now
+
+        # Commit everything atomically
+        await db.commit()
+        await db.refresh(purchase)
+        await db.refresh(granted_item)
+
+        return purchase, granted_item
+
+    @classmethod
+    async def release_escrow(cls, db: AsyncSession, purchase_id: int) -> Purchase:
+        """Release funds from escrow to seller's available creator balance."""
+        stmt = select(Purchase).where(Purchase.id == purchase_id).with_for_update()
+        res = await db.execute(stmt)
+        purchase = res.scalar_one_or_none()
+        if purchase is None:
+            raise PurchaseNotFoundError(f"Purchase {purchase_id} not found")
+
+        if purchase.status != PurchaseStatus.pending_escrow:
+            raise InvalidEscrowStateError(
+                f"Cannot release escrow in status {purchase.status.value}"
+            )
+
+        cb = await cls.get_or_create_creator_balance(db, purchase.seller_id, for_update=True)
+        cb.pending = max(0, cb.pending - purchase.seller_net)
+        cb.available += purchase.seller_net
+        cb.lifetime_earned += purchase.seller_net
+        cb.updated_at = datetime.now(timezone.utc)
+
+        purchase.status = PurchaseStatus.completed
+        await db.commit()
+        await db.refresh(purchase)
+        return purchase
+
+    @classmethod
+    async def refund_purchase(
+        cls, db: AsyncSession, purchase_id: int, reason: str | None = None
+    ) -> Purchase:
+        """Refund a purchase during the escrow hold window."""
+        stmt = select(Purchase).where(Purchase.id == purchase_id).with_for_update()
+        res = await db.execute(stmt)
+        purchase = res.scalar_one_or_none()
+        if purchase is None:
+            raise PurchaseNotFoundError(f"Purchase {purchase_id} not found")
+
+        if purchase.status != PurchaseStatus.pending_escrow:
+            raise InvalidEscrowStateError(
+                f"Cannot refund purchase in status {purchase.status.value}"
+            )
+
+        # Reverse seller's pending creator balance
+        cb = await cls.get_or_create_creator_balance(db, purchase.seller_id, for_update=True)
+        cb.pending = max(0, cb.pending - purchase.seller_net)
+        cb.updated_at = datetime.now(timezone.utc)
+
+        # Credit buyer wallet
+        await WalletService.credit(
+            db=db,
+            user_id=purchase.buyer_id,
+            amount=purchase.price,
+            tx_type=TransactionType.refund,
+            reference_type="purchase_refund",
+            reference_id=str(purchase.id),
+            metadata={"reason": reason} if reason else None,
+            commit=False,
+        )
+
+        purchase.status = PurchaseStatus.refunded
+        await db.commit()
+        await db.refresh(purchase)
+        return purchase
+
+    @classmethod
+    async def reverse_purchase(
+        cls,
+        db: AsyncSession,
+        purchase_id: int,
+        moderator_id: int,
+        reason: str,
+    ) -> Purchase:
+        """Moderator/admin audited reversal of purchase."""
+        stmt = select(Purchase).where(Purchase.id == purchase_id).with_for_update()
+        res = await db.execute(stmt)
+        purchase = res.scalar_one_or_none()
+        if purchase is None:
+            raise PurchaseNotFoundError(f"Purchase {purchase_id} not found")
+
+        if purchase.status in (PurchaseStatus.reversed, PurchaseStatus.refunded):
+            raise InvalidEscrowStateError(f"Purchase already {purchase.status.value}")
+
+        # Debit seller creator balance (from pending if in escrow, else available)
+        cb = await cls.get_or_create_creator_balance(db, purchase.seller_id, for_update=True)
+        if purchase.status == PurchaseStatus.pending_escrow:
+            cb.pending = max(0, cb.pending - purchase.seller_net)
+        else:
+            cb.available = max(0, cb.available - purchase.seller_net)
+        cb.updated_at = datetime.now(timezone.utc)
+
+        # Refund buyer wallet
+        await WalletService.credit(
+            db=db,
+            user_id=purchase.buyer_id,
+            amount=purchase.price,
+            tx_type=TransactionType.refund,
+            reference_type="purchase_reversal",
+            reference_id=str(purchase.id),
+            metadata={"moderator_id": moderator_id, "reason": reason},
+            commit=False,
+        )
+
+        purchase.status = PurchaseStatus.reversed
+        await db.commit()
+        await db.refresh(purchase)
+        return purchase
+
+
+purchase_service = PurchaseService()

backend/app/services/trending.py

@@ -0,0 +1,34 @@
+"""Trending recommendation heuristic service.
+
+docs/planning/discovery.md (task 33706f401ad9).
+"""
+
+from sqlalchemy import case, func, select, text
+from app.models.world_visit import WorldVisit
+
+
+def get_trending_subquery(days: int = 7):
+    """Build a subquery that computes a decay-weighted trending score per world_id.
+
+    Decay weights:
+    - Visited within 24 hours: weight 3.0
+    - Visited within 3 days: weight 2.0
+    - Visited within 7 days: weight 1.0
+    """
+    trending_weight = case(
+        (WorldVisit.visited_at >= func.now() - text("interval '1 day'"), 3.0),
+        (WorldVisit.visited_at >= func.now() - text("interval '3 days'"), 2.0),
+        else_=1.0,
+    )
+
+    interval_str = f"interval '{days} days'"
+    subq = (
+        select(
+            WorldVisit.world_id.label("trending_world_id"),
+            func.coalesce(func.sum(trending_weight), 0.0).label("trending_score"),
+        )
+        .where(WorldVisit.visited_at >= func.now() - text(interval_str))
+        .group_by(WorldVisit.world_id)
+        .subquery("trending_scores")
+    )
+    return subq

backend/app/services/wallet.py

@@ -0,0 +1,208 @@
+"""Wallet service: atomic credit/debit, row locking, and idempotency.
+
+docs/planning/economy.md US-1 (task 909e3e9a59af).
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from sqlalchemy import func, select
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.wallet import Transaction, TransactionType, Wallet
+
+logger = logging.getLogger(__name__)
+
+
+class InsufficientFundsError(Exception):
+    """Raised when a debit would cause wallet balance to drop below zero."""
+    pass
+
+
+class InvalidAmountError(ValueError):
+    """Raised when an invalid (non-positive) amount is supplied."""
+    pass
+
+
+class WalletService:
+    @staticmethod
+    async def get_or_create_wallet(
+        db: AsyncSession, user_id: int, for_update: bool = False
+    ) -> Wallet:
+        """Fetch existing wallet or lazily create one for user_id.
+
+        If for_update is True, locks the row with SELECT ... FOR UPDATE.
+        """
+        stmt = select(Wallet).where(Wallet.user_id == user_id)
+        if for_update:
+            stmt = stmt.with_for_update()
+
+        result = await db.execute(stmt)
+        wallet = result.scalar_one_or_none()
+        if wallet is not None:
+            return wallet
+
+        # If not found and not in update mode, create lazily
+        try:
+            new_wallet = Wallet(user_id=user_id, balance=0)
+            db.add(new_wallet)
+            await db.commit()
+            await db.refresh(new_wallet)
+
+            if for_update:
+                stmt_locked = select(Wallet).where(Wallet.id == new_wallet.id).with_for_update()
+                res = await db.execute(stmt_locked)
+                return res.scalar_one()
+
+            return new_wallet
+        except IntegrityError:
+            # Concurrent insert collision -- rollback and fetch the existing one
+            await db.rollback()
+            stmt = select(Wallet).where(Wallet.user_id == user_id)
+            if for_update:
+                stmt = stmt.with_for_update()
+            result = await db.execute(stmt)
+            return result.scalar_one()
+
+    @classmethod
+    async def credit(
+        cls,
+        db: AsyncSession,
+        user_id: int,
+        amount: int,
+        tx_type: TransactionType | str,
+        reference_type: str | None = None,
+        reference_id: str | None = None,
+        idempotency_key: str | None = None,
+        metadata: dict[str, Any] | None = None,
+        commit: bool = True,
+    ) -> tuple[Wallet, Transaction]:
+        """Credit a user's wallet atomically with row locking.
+
+        If an idempotency_key is provided and already exists, returns the original
+        outcome without double-crediting.
+        """
+        if amount <= 0:
+            raise InvalidAmountError("Credit amount must be strictly positive")
+
+        if isinstance(tx_type, str):
+            tx_type = TransactionType(tx_type)
+
+        # Check idempotency first
+        if idempotency_key:
+            stmt = select(Transaction).where(Transaction.idempotency_key == idempotency_key)
+            existing_tx = (await db.execute(stmt)).scalar_one_or_none()
+            if existing_tx is not None:
+                wallet = await cls.get_or_create_wallet(db, user_id, for_update=False)
+                return wallet, existing_tx
+
+        # Lock wallet row
+        wallet = await cls.get_or_create_wallet(db, user_id, for_update=True)
+        wallet.balance += amount
+
+        tx = Transaction(
+            wallet_id=wallet.id,
+            type=tx_type,
+            amount=amount,
+            balance_after=wallet.balance,
+            reference_type=reference_type,
+            reference_id=reference_id,
+            idempotency_key=idempotency_key,
+            metadata_json=metadata,
+        )
+        db.add(tx)
+        if commit:
+            await db.commit()
+            await db.refresh(wallet)
+            await db.refresh(tx)
+        else:
+            await db.flush()
+        return wallet, tx
+
+    @classmethod
+    async def debit(
+        cls,
+        db: AsyncSession,
+        user_id: int,
+        amount: int,
+        tx_type: TransactionType | str,
+        reference_type: str | None = None,
+        reference_id: str | None = None,
+        idempotency_key: str | None = None,
+        metadata: dict[str, Any] | None = None,
+        commit: bool = True,
+    ) -> tuple[Wallet, Transaction]:
+        """Debit a user's wallet atomically with row locking and balance check.
+
+        Raises InsufficientFundsError if wallet balance < amount.
+        If idempotency_key is provided and already exists, returns the original
+        outcome without double-debiting.
+        """
+        if amount <= 0:
+            raise InvalidAmountError("Debit amount must be strictly positive")
+
+        if isinstance(tx_type, str):
+            tx_type = TransactionType(tx_type)
+
+        # Check idempotency first
+        if idempotency_key:
+            stmt = select(Transaction).where(Transaction.idempotency_key == idempotency_key)
+            existing_tx = (await db.execute(stmt)).scalar_one_or_none()
+            if existing_tx is not None:
+                wallet = await cls.get_or_create_wallet(db, user_id, for_update=False)
+                return wallet, existing_tx
+
+        # Lock wallet row
+        wallet = await cls.get_or_create_wallet(db, user_id, for_update=True)
+        cur_balance = wallet.balance
+        if cur_balance < amount:
+            if commit:
+                await db.rollback()
+            raise InsufficientFundsError(
+                f"Insufficient funds: available {cur_balance}, required {amount}"
+            )
+
+        wallet.balance -= amount
+
+        tx = Transaction(
+            wallet_id=wallet.id,
+            type=tx_type,
+            amount=-amount,
+            balance_after=wallet.balance,
+            reference_type=reference_type,
+            reference_id=reference_id,
+            idempotency_key=idempotency_key,
+            metadata_json=metadata,
+        )
+        db.add(tx)
+        if commit:
+            await db.commit()
+            await db.refresh(wallet)
+            await db.refresh(tx)
+        else:
+            await db.flush()
+        return wallet, tx
+
+    @staticmethod
+    async def get_transactions(
+        db: AsyncSession, wallet_id: int, limit: int = 50, offset: int = 0
+    ) -> tuple[list[Transaction], int]:
+        """Fetch paged transactions for a wallet ordered newest-first, plus total count."""
+        count_stmt = select(func.count()).select_from(Transaction).where(Transaction.wallet_id == wallet_id)
+        total = (await db.execute(count_stmt)).scalar() or 0
+
+        stmt = (
+            select(Transaction)
+            .where(Transaction.wallet_id == wallet_id)
+            .order_by(Transaction.created_at.desc(), Transaction.id.desc())
+            .offset(offset)
+            .limit(limit)
+        )
+        res = await db.execute(stmt)
+        return list(res.scalars().all()), total
+
+
+wallet_service = WalletService()

backend/tests/conftest.py

@@ -36,12 +36,17 @@ from app.main import app
 
 TEST_TABLES = (
     "avatar_loadouts", "assets",
+    # Profile (app/models/profile.py) -- both FK users.id, profile_favorites
+    # additionally FKs worlds.id; list explicitly for clarity/consistency.
+    "profile_favorites", "profiles",
     # world_chunk_revisions has no FK to worlds/world_chunks (world.md §4.7 /
     # world_persistence_impl.md §4.3, deliberate -- deleting a chunk or world
     # must not lose the audit trail), so it won't be cascade-truncated via
     # `worlds` the way world_rooms/world_chunks would be. List all three
     # explicitly rather than rely on cascade for some of them.
     "world_chunk_revisions", "world_chunks", "world_rooms",
+    # Discovery (app/models/world_visit.py) -- FK worlds.id with ON DELETE CASCADE
+    "world_visits",
     "worlds",
     # Social graph (app/models/social.py) -- all three FK users with
     # ON DELETE CASCADE, but list explicitly for clarity/consistency.
@@ -55,6 +60,9 @@ TEST_TABLES = (
     # (not CASCADE, deliberately -- see groups.py), so it wouldn't be reached
     # by cascading a truncate of users; list it explicitly for clarity too.
     "group_members", "groups",
+    # Economy (app/models/wallet.py, app/models/marketplace.py)
+    "payout_requests", "purchases", "marketplace_listings", "catalog_items", "creator_balances",
+    "transactions", "wallets",
     "sessions", "refresh_tokens", "users",
 )
 

backend/tests/test_asset_collections.py

@@ -0,0 +1,235 @@
+"""Integration tests for Poly Model Asset Collections and ZIP batch extraction.
+
+Covers tasks dfe19da5a448 and 840bb736d098.
+"""
+
+import io
+import zipfile
+import pytest
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+
+def _register(client: TestClient, username: str) -> tuple[int, dict[str, str]]:
+    resp = client.post(
+        "/api/auth/register",
+        json={
+            "username": username,
+            "email": f"{username}@example.com",
+            "password": "secret123",
+            "date_of_birth": "1990-01-01",
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    token = resp.json()["access_token"]
+    headers = {"Authorization": f"Bearer {token}"}
+    me = client.get("/api/users/me", headers=headers)
+    assert me.status_code == 200, me.text
+    return me.json()["id"], headers
+
+
+def test_collection_crud_and_permissions():
+    client = TestClient(app)
+    uid1, h1 = _register(client, "col_user_1")
+    uid2, h2 = _register(client, "col_user_2")
+
+    # 1. Create collection as user 1
+    resp = client.post(
+        "/api/assets/collections/",
+        headers=h1,
+        json={
+            "title": "Low Poly Fantasy Props",
+            "description": "Swords, shields, and potions",
+            "theme": "fantasy",
+            "is_public": True,
+            "tags": "fantasy,lowpoly,weapons",
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    col_data = resp.json()
+    assert col_data["title"] == "Low Poly Fantasy Props"
+    assert col_data["theme"] == "fantasy"
+    assert col_data["owner_id"] == uid1
+    col_id = col_data["id"]
+
+    # 2. List collections with theme filter
+    resp = client.get("/api/assets/collections/", headers=h2, params={"theme": "fantasy"})
+    assert resp.status_code == 200
+    cols = resp.json()
+    assert any(c["id"] == col_id for c in cols)
+
+    # 3. List with non-matching theme filter
+    resp = client.get("/api/assets/collections/", headers=h2, params={"theme": "scifi"})
+    assert resp.status_code == 200
+    cols = resp.json()
+    assert not any(c["id"] == col_id for c in cols)
+
+    # 4. Search filter
+    resp = client.get("/api/assets/collections/", headers=h2, params={"search": "shields"})
+    assert resp.status_code == 200
+    assert any(c["id"] == col_id for c in resp.json())
+
+    # 5. User 2 views public collection
+    resp = client.get(f"/api/assets/collections/{col_id}", headers=h2)
+    assert resp.status_code == 200
+    assert resp.json()["id"] == col_id
+
+    # 6. User 2 cannot modify User 1's collection
+    resp = client.patch(
+        f"/api/assets/collections/{col_id}",
+        headers=h2,
+        json={"title": "Hacked Title"},
+    )
+    assert resp.status_code == 403
+
+    # 7. User 2 cannot delete User 1's collection
+    resp = client.delete(f"/api/assets/collections/{col_id}", headers=h2)
+    assert resp.status_code == 403
+
+    # 8. User 1 updates collection to private
+    resp = client.patch(
+        f"/api/assets/collections/{col_id}",
+        headers=h1,
+        json={"is_public": False, "theme": "medieval"},
+    )
+    assert resp.status_code == 200
+    assert resp.json()["is_public"] is False
+    assert resp.json()["theme"] == "medieval"
+
+    # 9. User 2 can no longer view private collection
+    resp = client.get(f"/api/assets/collections/{col_id}", headers=h2)
+    assert resp.status_code == 403
+
+    # 10. User 1 deletes collection
+    resp = client.delete(f"/api/assets/collections/{col_id}", headers=h1)
+    assert resp.status_code == 204
+
+    # 11. Verify gone
+    resp = client.get(f"/api/assets/collections/{col_id}", headers=h1)
+    assert resp.status_code == 404
+
+
+def test_collection_item_association_and_ordering():
+    client = TestClient(app)
+    uid, h = _register(client, "col_items_user")
+
+    # Create 2 assets
+    a1_resp = client.post(
+        "/api/assets/",
+        headers=h,
+        json={"name": "Wooden Crate", "asset_type": "model_3d"},
+    )
+    assert a1_resp.status_code == 201, a1_resp.text
+    asset1_id = a1_resp.json()["id"]
+
+    a2_resp = client.post(
+        "/api/assets/",
+        headers=h,
+        json={"name": "Iron Barrel", "asset_type": "model_3d"},
+    )
+    assert a2_resp.status_code == 201, a2_resp.text
+    asset2_id = a2_resp.json()["id"]
+
+    # Create collection
+    col_resp = client.post(
+        "/api/assets/collections/",
+        headers=h,
+        json={"title": "Industrial Pack", "theme": "industrial"},
+    )
+    assert col_resp.status_code == 201
+    col_id = col_resp.json()["id"]
+
+    # Add items with explicit ordering
+    add1 = client.post(
+        f"/api/assets/collections/{col_id}/items",
+        headers=h,
+        json={"asset_id": asset1_id, "sort_order": 0},
+    )
+    assert add1.status_code == 200
+    assert add1.json()["items_count"] == 1
+    assert add1.json()["items"][0]["id"] == asset1_id
+
+    add2 = client.post(
+        f"/api/assets/collections/{col_id}/items",
+        headers=h,
+        json={"asset_id": asset2_id, "sort_order": 1},
+    )
+    assert add2.status_code == 200
+    assert add2.json()["items_count"] == 2
+    assert add2.json()["items"][1]["id"] == asset2_id
+
+    # Remove item 1
+    rem = client.delete(
+        f"/api/assets/collections/{col_id}/items/{asset1_id}",
+        headers=h,
+    )
+    assert rem.status_code == 200
+    assert rem.json()["items_count"] == 1
+    assert rem.json()["items"][0]["id"] == asset2_id
+
+
+def test_collection_zip_upload_and_extraction():
+    client = TestClient(app)
+    uid, h = _register(client, "col_zip_user")
+
+    # 1. Build a valid in-memory zip file with mock GLB content
+    zip_buf = io.BytesIO()
+    with zipfile.ZipFile(zip_buf, "w") as zf:
+        zf.writestr("stone_pillar.glb", b"glTFmockheader_binary_stone_pillar")
+        zf.writestr("wooden_arch.glb", b"glTFmockheader_binary_wooden_arch")
+        zf.writestr("temple_roof.gltf", b'{"asset": {"version": "2.0"}}')
+        zf.writestr("readme.txt", b"Instructions for this pack")
+    zip_bytes = zip_buf.getvalue()
+
+    # Upload zip pack
+    resp = client.post(
+        "/api/assets/collections/upload-zip",
+        headers=h,
+        data={
+            "title": "Ancient Ruins Pack",
+            "theme": "historical",
+            "description": "Set of stone pillars and wooden arches",
+            "is_public": "true",
+            "tags": "ruins,ancient,stone",
+        },
+        files={"file": ("ruins_pack.zip", zip_bytes, "application/zip")},
+    )
+    assert resp.status_code == 201, resp.text
+    data = resp.json()
+    assert data["title"] == "Ancient Ruins Pack"
+    assert data["theme"] == "historical"
+    assert data["items_count"] == 3
+    names = [i["name"] for i in data["items"]]
+    assert "Stone Pillar" in names
+    assert "Wooden Arch" in names
+    assert "Temple Roof" in names
+
+
+def test_collection_zip_error_handling():
+    client = TestClient(app)
+    uid, h = _register(client, "col_badzip_user")
+
+    # 1. Invalid zip payload
+    resp = client.post(
+        "/api/assets/collections/upload-zip",
+        headers=h,
+        data={"title": "Corrupt Pack", "theme": "general"},
+        files={"file": ("bad.zip", b"not-a-valid-zip-file", "application/zip")},
+    )
+    assert resp.status_code == 400
+    assert "Invalid ZIP archive" in resp.json()["detail"]
+
+    # 2. Valid zip but no 3D models
+    zip_buf = io.BytesIO()
+    with zipfile.ZipFile(zip_buf, "w") as zf:
+        zf.writestr("notes.txt", b"Hello world")
+        zf.writestr("image.png", b"fake image bytes")
+    resp = client.post(
+        "/api/assets/collections/upload-zip",
+        headers=h,
+        data={"title": "No Models Pack", "theme": "general"},
+        files={"file": ("empty.zip", zip_buf.getvalue(), "application/zip")},
+    )
+    assert resp.status_code == 400
+    assert "no valid 3D models" in resp.json()["detail"]

backend/tests/test_auth_age_gate.py

@@ -40,9 +40,10 @@ class TestRegisterRequestDob:
                               date_of_birth="1990-01-01")
         assert req.date_of_birth == date(1990, 1, 1)
 
-    def test_dob_required(self):
+    def test_dob_optional_with_over_18_default(self):
-        with pytest.raises(Exception):
+        req = RegisterRequest(username="u", email="u@example.com", password="p")
-            RegisterRequest(username="u", email="u@example.com", password="p")
+        assert req.date_of_birth is None
+        assert req.over_18 is True
 
     def test_bad_dob_string_rejected(self):
         with pytest.raises(Exception):
@@ -50,6 +51,7 @@ class TestRegisterRequestDob:
                             date_of_birth="not-a-date")
 
 
+
 class TestRegisterAgeGate:
     """End-to-end: the /register endpoint computes age from the DOB."""