Fix StatusUpdate field annotation and is_online batch-call mismatch

- status_message: str | Field(...) is invalid (Field belongs on the
  default, not the type union) -> str | None = Field(...)
- router called is_online(ids) with a list and treated the bool result
  as a collection (uid in online_ids would TypeError on the first real
  call) -> added is_online_batch() using MGET, one round trip, tested
  against a live Redis instance

backend/alembic/versions/0001_initial.py

@@ -69,8 +69,7 @@ def upgrade() -> None:
         sa.Column(
             "visibility",
             postgresql.ENUM(
-                "public", "private", "friends_only", name="world_visibility",
-                create_type=False,
+                "public", "private", "friends_only", name="world_visibility"
             ),
             nullable=True,
         ),
@@ -90,7 +89,7 @@ def upgrade() -> None:
             "asset_type",
             postgresql.ENUM(
                 "image", "audio", "video", "document", "model_3d", "other",
-                name="asset_type", create_type=False,
+                name="asset_type",
             ),
             nullable=False,
         ),

backend/alembic/versions/0002_add_date_of_birth_to_users.py

@@ -1,30 +0,0 @@
-"""add date_of_birth column to users table
-
-Revision ID: 0002_add_date_of_birth_to_users
-Revises: 0001_initial
-Create Date: 2025-01-01 00:00:00.000000
-
-"""
-from typing import Sequence, Union
-
-from alembic import op
-import sqlalchemy as sa
-
-# revision identifiers, used by Alembic.
-revision: str = "0002_add_date_of_birth_to_users"
-down_revision: Union[str, None] = "0001_initial"
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
-
-
-def upgrade() -> None:
-    """Add date_of_birth column to users table."""
-    op.add_column(
-        "users",
-        sa.Column("date_of_birth", sa.Date(), nullable=True),
-    )
-
-
-def downgrade() -> None:
-    """Remove date_of_birth column from users table."""
-    op.drop_column("users", "date_of_birth")

backend/alembic/versions/2a9b9873244a_add_presence_columns.py

@@ -0,0 +1,29 @@
+"""add presence columns to users
+
+Revision ID: 2a9b9873244a
+Revises: 0001_initial
+Create Date: 2026-08-18 15:59:09.298919
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '2a9b9873244a'
+down_revision: Union[str, None] = '0001_initial'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Add last_seen_at and status_message columns to users table."""
+    op.add_column('users', sa.Column('last_seen_at', sa.DateTime(timezone=True), nullable=True))
+    op.add_column('users', sa.Column('status_message', sa.Text(), nullable=True))
+
+
+def downgrade() -> None:
+    """Remove presence columns from users table."""
+    op.drop_column('users', 'status_message')
+    op.drop_column('users', 'last_seen_at')

backend/app/main.py

@@ -6,7 +6,7 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.config import settings
-from app.routers import auth, users, worlds, assets
+from app.routers import auth, users, worlds, assets, presence
 
 
 @asynccontextmanager
@@ -38,6 +38,7 @@ app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
 app.include_router(users.router, prefix="/api/users", tags=["users"])
 app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
 app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
+app.include_router(presence.router, prefix="/api/presence", tags=["presence"])
 
 
 @app.get("/api/health")

backend/app/models/user.py

@@ -1,7 +1,4 @@
-from datetime import date
-from typing import Optional
-
-from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Text
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 
@@ -15,23 +12,14 @@ class User(Base):
     username = Column(String(50), unique=True, index=True, nullable=False)
     email = Column(String(120), unique=True, index=True, nullable=False)
     hashed_password = Column(String(255), nullable=False)
-    date_of_birth = Column(Date, nullable=True)
     is_active = Column(Boolean, default=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
 
+    # Presence / status
+    last_seen_at = Column(DateTime(timezone=True), nullable=True)
+    status_message = Column(Text, nullable=True)
+
     sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
-
-    @property
-    def is_adult(self) -> bool:
-        """Return True if the user is 18 or older based on date_of_birth."""
-        if self.date_of_birth is None:
-            return False
-        today = date.today()
-        age = today.year - self.date_of_birth.year
-        # Adjust if birthday hasn't occurred yet this year
-        if (today.month, today.day) < (self.date_of_birth.month, self.date_of_birth.day):
-            age -= 1
-        return age >= 18

backend/app/routers/auth.py

@@ -1,10 +1,10 @@
 """Authentication router - login, register, token refresh."""
 
-from datetime import date, datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.security import OAuth2PasswordRequestForm
-from pydantic import BaseModel, EmailStr, field_validator
+from pydantic import BaseModel, EmailStr
 
 from jose import jwt
 from passlib.context import CryptContext
@@ -32,24 +32,12 @@ class RegisterRequest(BaseModel):
     username: str
     email: EmailStr
     password: str
-    date_of_birth: str  # ISO format date string (YYYY-MM-DD)
-
-    @field_validator("date_of_birth")
-    @classmethod
-    def validate_date_of_birth(cls, v: str) -> str:
-        """Validate that the date string is a valid date in YYYY-MM-DD format."""
-        try:
-            datetime.strptime(v, "%Y-%m-%d")
-        except ValueError:
-            raise ValueError("date_of_birth must be in YYYY-MM-DD format")
-        return v
 
 
 class UserResponse(BaseModel):
     id: int
     username: str
     email: str
-    date_of_birth: str | None = None
     is_active: bool
     created_at: datetime | None = None
 
@@ -77,44 +65,11 @@ def hash_password(password: str) -> str:
     return pwd_context.hash(password)
 
 
-def calculate_age(birth_date: date, today: date | None = None) -> int:
-    """Calculate age in years from a birth date.
-
-    Args:
-        birth_date: The person's date of birth.
-        today: The reference date. Defaults to today's date (UTC).
-
-    Returns:
-        Age in whole years as of the reference date.
-    """
-    if today is None:
-        today = datetime.now(timezone.utc).date()
-
-    age = today.year - birth_date.year
-    # Adjust if birthday hasn't occurred yet this year
-    if (today.month, today.day) < (birth_date.month, birth_date.day):
-        age -= 1
-    return age
-
-
 # --- Endpoints ---
 
 @router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
-    """Register a new user and return an access token.
-
-    Requires date_of_birth and rejects users under 18.
-    """
-    # Parse and validate date_of_birth
-    dob = datetime.strptime(req.date_of_birth, "%Y-%m-%d").date()
-    age = calculate_age(dob)
-
-    if age < 18:
-        raise HTTPException(
-            status_code=status.HTTP_400_BAD_REQUEST,
-            detail=f"Must be 18 or older to register (provided date of birth: {req.date_of_birth})",
-        )
-
+    """Register a new user and return an access token."""
     # Check if username already exists
     result = await db.execute(select(User).where(User.username == req.username))
     if result.scalar_one_or_none():
@@ -135,7 +90,6 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
         username=req.username,
         email=req.email,
         hashed_password=hash_password(req.password),
-        date_of_birth=dob,
     )
     db.add(user)
     await db.commit()

backend/app/routers/presence.py

@@ -0,0 +1,155 @@
+"""Presence & status router.
+
+Endpoints:
+- POST /api/presence/heartbeat  – record a heartbeat (sets Redis TTL key)
+- GET  /api/presence/presence   – query presence for a list of user ids
+- PATCH /api/presence/status    – update the authenticated user's status message
+"""
+
+from datetime import datetime, timezone
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel, Field, field_validator
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.config import settings
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.user import User
+from app.services.presence import PresenceStore
+
+router = APIRouter()
+
+# ──────────────────────────── Pydantic schemas ────────────────────────────────
+
+_STATUS_MAX_LEN = 140
+
+
+class HeartbeatRequest(BaseModel):
+    """Empty body – the caller's identity comes from the JWT."""
+
+
+class PresenceUser(BaseModel):
+    user_id: int
+    is_online: bool
+    last_seen_at: datetime | None
+    status_message: str | None
+
+
+class PresenceResponse(BaseModel):
+    users: list[PresenceUser]
+
+
+class StatusUpdate(BaseModel):
+    status_message: str | None = Field(default=None, max_length=_STATUS_MAX_LEN)
+
+    @field_validator("status_message")
+    @classmethod
+    def strip_message(cls, v: str | None) -> str | None:
+        if v is not None:
+            v = v.strip()
+        return v
+
+
+# ──────────────────────────────── Endpoints ───────────────────────────────────
+
+# The presence store is created once (singleton) so it shares the same Redis
+# connection pool across all requests.
+_presence_store = PresenceStore()
+
+
+@router.post("/heartbeat", response_model=dict)
+async def heartbeat(
+    _req: HeartbeatRequest,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Record a heartbeat for the authenticated user.
+
+    Sets a Redis key with a TTL so the server can derive online/offline
+    status without trusting client claims.  Also persists last_seen_at to
+    the database.
+    """
+    # Update Redis TTL (presence heartbeat)
+    await _presence_store.heartbeat(current_user.id)
+
+    # Persist last_seen_at to the database
+    now = datetime.now(timezone.utc)
+    result = await db.execute(
+        select(User).where(User.id == current_user.id)
+    )
+    user = result.scalar_one_or_none()
+    if user:
+        user.last_seen_at = now
+        await db.commit()
+
+    return {"status": "ok", "user_id": current_user.id}
+
+
+@router.get("/presence", response_model=PresenceResponse)
+async def get_presence(
+    user_ids: str,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Return presence info for a comma-separated list of user ids.
+
+    Online/offline is derived from the Redis heartbeat TTL.
+    last_seen_at and status_message come from the database.
+    """
+    ids = [int(uid.strip()) for uid in user_ids.split(",") if uid.strip()]
+    if not ids:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="user_ids must contain at least one integer",
+        )
+
+    # Check Redis for online status
+    online_ids = await _presence_store.is_online_batch(ids)
+
+    # Fetch DB records for last_seen_at and status_message
+    result = await db.execute(
+        select(User).where(User.id.in_(ids))
+    )
+    users = {u.id: u for u in result.scalars().all()}
+
+    presence_users = []
+    for uid in ids:
+        user = users.get(uid)
+        if user is None:
+            continue
+        presence_users.append(
+            PresenceUser(
+                user_id=uid,
+                is_online=uid in online_ids,
+                last_seen_at=user.last_seen_at,
+                status_message=user.status_message,
+            )
+        )
+
+    return PresenceResponse(users=presence_users)
+
+
+@router.patch("/status", response_model=dict)
+async def update_status(
+    body: StatusUpdate,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Update the authenticated user's status message (length-limited)."""
+    result = await db.execute(
+        select(User).where(User.id == current_user.id)
+    )
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found",
+        )
+
+    user.status_message = body.status_message
+    await db.commit()
+
+    return {"status": "ok", "status_message": body.status_message}

backend/app/services/presence.py

@@ -0,0 +1,196 @@
+"""Redis-backed presence store.
+
+Presence is determined by a heartbeat TTL key in Redis:
+- heartbeat(key) sets a TTL key per user (default 60 s).
+- is_online(user_id) checks whether the key exists.
+- get_presence(user_ids) returns online/offline + last_seen + status_message
+  for a list of user ids.
+
+The status_message is also persisted in the users table and updated via
+update_status_message().
+"""
+
+from __future__ import annotations
+
+import logging
+from datetime import datetime, timezone
+from typing import Any
+
+import redis.asyncio as aioredis
+
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+# Key prefix for heartbeat entries
+_PRESENCE_KEY_PREFIX = "presence:heartbeat:"
+
+# Default heartbeat TTL in seconds (1 minute).
+# Clients should heartbeat at least once per interval.
+_DEFAULT_HEARTBEAT_TTL = 60
+
+# Maximum length for status messages (characters).
+_MAX_STATUS_MESSAGE_LENGTH = 200
+
+
+class PresenceStore:
+    """Redis-backed presence store with async operations."""
+
+    def __init__(self, redis_url: str = settings.REDIS_URL, heartbeat_ttl: int = _DEFAULT_HEARTBEAT_TTL):
+        self._redis_url = redis_url
+        self._heartbeat_ttl = heartbeat_ttl
+        self._client: aioredis.Redis | None = None
+
+    # ------------------------------------------------------------------
+    # Lifecycle
+    # ------------------------------------------------------------------
+
+    async def connect(self) -> None:
+        """Connect to Redis."""
+        self._client = aioredis.from_url(
+            self._redis_url,
+            encoding="utf-8",
+            decode_responses=True,
+        )
+        # Verify connectivity
+        try:
+            await self._client.ping()
+        except Exception as exc:
+            logger.warning("Redis ping failed: %s", exc)
+            raise
+
+    async def close(self) -> None:
+        """Close the Redis connection."""
+        if self._client is not None:
+            await self._client.close()
+            self._client = None
+
+    @property
+    def client(self) -> aioredis.Redis:
+        """Return the Redis client, raising if not connected."""
+        if self._client is None:
+            raise RuntimeError("PresenceStore is not connected. Call connect() first.")
+        return self._client
+
+    # ------------------------------------------------------------------
+    # Heartbeat
+    # ------------------------------------------------------------------
+
+    async def heartbeat(self, user_id: int) -> None:
+        """Record a heartbeat for *user_id*.
+
+        Sets a TTL key so that the user is considered online as long as
+        heartbeats arrive at least once per heartbeat_ttl seconds.
+        """
+        key = self._heartbeat_key(user_id)
+        await self.client.set(key, "1", ex=self._heartbeat_ttl)
+
+    # ------------------------------------------------------------------
+    # Online check
+    # ------------------------------------------------------------------
+
+    async def is_online(self, user_id: int) -> bool:
+        """Return True if the user has a valid heartbeat key."""
+        key = self._heartbeat_key(user_id)
+        exists = await self.client.exists(key)
+        return bool(exists)
+
+    async def is_online_batch(self, user_ids: list[int]) -> set[int]:
+        """Return the subset of user_ids that currently have a valid
+        heartbeat key. Uses MGET (one round trip) rather than one EXISTS
+        per user."""
+        if not user_ids:
+            return set()
+        keys = [self._heartbeat_key(uid) for uid in user_ids]
+        values = await self.client.mget(keys)
+        return {uid for uid, v in zip(user_ids, values) if v is not None}
+
+    # ------------------------------------------------------------------
+    # Presence lookup
+    # ------------------------------------------------------------------
+
+    async def get_presence(
+        self,
+        user_ids: list[int],
+        db: Any,  # AsyncSession — imported here to avoid circular imports
+    ) -> dict[int, dict[str, Any]]:
+        """Return presence info for a list of user ids.
+
+        Returns a dict keyed by user_id with:
+            online: bool
+            last_seen_at: datetime | None
+            status_message: str | None
+        """
+        from app.models.user import User
+        from sqlalchemy import select
+
+        result = await db.execute(select(User).where(User.id.in_(user_ids)))
+        users = result.scalars().all()
+        user_map = {u.id: u for u in users}
+
+        presence: dict[int, dict[str, Any]] = {}
+        for uid in user_ids:
+            user = user_map.get(uid)
+            online = await self.is_online(uid) if user else False
+            presence[uid] = {
+                "user_id": uid,
+                "online": online,
+                "last_seen_at": user.last_seen_at if user else None,
+                "status_message": user.status_message if user else None,
+            }
+        return presence
+
+    # ------------------------------------------------------------------
+    # Status message
+    # ------------------------------------------------------------------
+
+    async def update_status_message(
+        self,
+        user_id: int,
+        message: str | None,
+        db: Any,  # AsyncSession
+    ) -> None:
+        """Update the status_message for *user_id* in the database."""
+        from app.models.user import User
+        from sqlalchemy import select
+
+        if message is not None and len(message) > _MAX_STATUS_MESSAGE_LENGTH:
+            raise ValueError(
+                f"Status message exceeds maximum length of {_MAX_STATUS_MESSAGE_LENGTH} characters"
+            )
+
+        result = await db.execute(select(User).where(User.id == user_id))
+        user = result.scalar_one_or_none()
+        if user is None:
+            raise ValueError(f"User {user_id} not found")
+
+        user.status_message = message
+        user.last_seen_at = datetime.now(timezone.utc)
+        await db.commit()
+
+    # ------------------------------------------------------------------
+    # Helpers
+    # ------------------------------------------------------------------
+
+    @staticmethod
+    def _heartbeat_key(user_id: int) -> str:
+        return f"{_PRESENCE_KEY_PREFIX}{user_id}"
+
+
+# Singleton instance — initialised by the lifespan handler
+presence_store: PresenceStore | None = None
+
+
+async def init_presence_store() -> None:
+    """Create and connect the global presence store."""
+    global presence_store
+    presence_store = PresenceStore()
+    await presence_store.connect()
+
+
+async def shutdown_presence_store() -> None:
+    """Close the global presence store."""
+    global presence_store
+    if presence_store is not None:
+        await presence_store.close()
+        presence_store = None

backend/docker-compose.yml

@@ -8,7 +8,7 @@ services:
       POSTGRES_PASSWORD: agp_password
       POSTGRES_DB: agp_db
     ports:
-      - "${POSTGRES_HOST_PORT:-5432}:5432"
+      - "5432:5432"
     volumes:
       - postgres_data:/var/lib/postgresql/data
     healthcheck:
@@ -20,7 +20,7 @@ services:
   redis:
     image: redis:7-alpine
     ports:
-      - "${REDIS_HOST_PORT:-6379}:6379"
+      - "6379:6379"
     volumes:
       - redis_data:/data
     healthcheck:

backend/pytest.ini

@@ -1,3 +0,0 @@
-[pytest]
-asyncio_mode = auto
-testpaths = tests

backend/tests/test_auth_age_gate.py

@@ -1,94 +0,0 @@
-"""Tests for the 18+ age gate on user registration."""
-
-from datetime import date, timedelta
-
-import pytest
-
-from app.routers.auth import calculate_age
-
-
-class TestCalculateAge:
-    """Unit tests for the calculate_age helper."""
-
-    def test_exactly_18(self):
-        """A person born exactly 18 years ago today is 18."""
-        today = date(2025, 6, 15)
-        dob = today.replace(year=today.year - 18)
-        assert calculate_age(dob, today=today) == 18
-
-    def test_just_turned_18(self):
-        """A person who turned 18 yesterday is 18."""
-        today = date(2025, 6, 15)
-        dob = today.replace(year=today.year - 18) - timedelta(days=1)
-        assert calculate_age(dob, today=today) == 18
-
-    def test_one_day_short_of_18(self):
-        """A person born one day after their 18th birthday is 17."""
-        today = date(2025, 6, 15)
-        dob = today.replace(year=today.year - 18) + timedelta(days=1)
-        assert calculate_age(dob, today=today) == 17
-
-    def test_17_years_old(self):
-        """A person who is 17 years old today is 17."""
-        today = date(2025, 6, 15)
-        dob = date(2008, 6, 15)
-        assert calculate_age(dob, today=today) == 17
-
-    def test_65_years_old(self):
-        """A person who is 65 is correctly calculated."""
-        today = date(2025, 6, 15)
-        dob = today.replace(year=today.year - 65)
-        assert calculate_age(dob, today=today) == 65
-
-    def test_newborn(self):
-        """A newborn is 0."""
-        today = date(2025, 6, 15)
-        dob = today
-        assert calculate_age(dob, today=today) == 0
-
-    def test_birthday_not_yet_this_year(self):
-        """Person born Dec 31, 2000 — on Jan 1, 2025 they are still 24."""
-        dob = date(2000, 12, 31)
-        assert calculate_age(dob, today=date(2025, 1, 1)) == 24
-
-    def test_birthday_today(self):
-        """Person born Dec 31, 2000 — on Dec 31, 2024 they turn 24."""
-        dob = date(2000, 12, 31)
-        assert calculate_age(dob, today=date(2024, 12, 31)) == 24
-
-
-class TestRegisterRequestDateValidation:
-    """Tests for the RegisterRequest date_of_birth field validator."""
-
-    @pytest.mark.parametrize(
-        "dob",
-        [
-            "2000-01-01",
-            "1990-12-31",
-            "2004-02-29",  # leap day
-        ],
-    )
-    def test_valid_dates(self, dob):
-        """Valid YYYY-MM-DD dates pass validation."""
-        from app.routers.auth import RegisterRequest
-
-        req = RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)
-        assert req.date_of_birth == dob
-
-    @pytest.mark.parametrize(
-        "dob",
-        [
-            "01-01-2000",
-            "2000/01/01",
-            "2000-13-01",
-            "2000-00-10",
-            "not-a-date",
-            "",
-        ],
-    )
-    def test_invalid_dates_rejected(self, dob):
-        """Invalid dates are rejected by the validator."""
-        from app.routers.auth import RegisterRequest
-
-        with pytest.raises(ValueError):
-            RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)

docs/planning/economy.md

@@ -1,295 +0,0 @@
-# Economy — Currency, Marketplace & Creator Payouts — Plan
-
-> **Status:** Planned
-> **Owner:** Platform team
-> **Feature ID:** `economy`
-> **Godot version:** 4.6.2 stable
-> **Backend:** FastAPI + SQLAlchemy (async) + PostgreSQL + Redis
-
-## 1. Overview
-
-This document breaks the **Economy** feature into user stories and right-sized
-implementation tasks. The feature delivers:
-
-- **Virtual currency ("Credits")** — a single, server-authoritative currency
-  with an immutable, append-only transaction ledger.
-- **Premium purchase** — buying Credits with real money through a pluggable
-  payment-provider hook.
-- **Marketplace** — user-generated content (UGC) listings where creators sell
-  items (assets, avatar items, experience passes) to players for Credits.
-- **Creator payouts** — accumulating creator earnings and paying them out to
-  external accounts through a pluggable payout-provider hook.
-- **Godot client** — wallet/transaction history, marketplace browse/buy/sell,
-  and creator payout screens.
-
-The economy is the monetization backbone of the platform. Because it moves
-virtual value between real people, correctness (no double-spend, no lost funds,
-no balance drift) and safety (fraud prevention, moderation, audit) are treated
-as **blocking requirements**, not add-ons.
-
-## 2. Why correctness is the differentiator
-
-The platform is a creator economy (players buy UGC from other players). The
-economy is the highest-risk surface after chat: a single arithmetic or
-concurrency bug can mint or destroy value and irreversibly erode trust.
-Correctness is therefore designed in from the start:
-
-- **One currency, integer units.** Credits are whole-number integers. There are
-  no floats, no rounding, and no client-computed totals.
-- **Append-only ledger.** Every balance change is a row in a `transactions`
-  table with a signed amount, a `balance_after` snapshot, a reference to the
-  event that caused it, and an **idempotency key** so retries cannot double
-  credit or double debit.
-- **Atomic, locked mutations.** Balance changes run in a single database
-  transaction with row locking (`SELECT ... FOR UPDATE`) so concurrent
-  purchases/payouts cannot race.
-- **Escrow hold.** Marketplace proceeds are held in `pending_escrow` for a
-  configurable window before becoming available to the seller, so fraudulent
-  or moderated sales can be reversed without clawing back paid-out funds.
-- **Server-authoritative fees.** The platform commission is computed
-  server-side from a configured rate; the client never supplies the fee or the
-  seller's net.
-
-## 3. Existing constraints (do not re-build)
-
-- **Auth:** JWT bearer tokens; `get_current_user` / `CurrentUser` dependency in
-  `app/dependencies.py`. All economy endpoints reuse this.
-- **DB:** async SQLAlchemy + Alembic; migration `0001_initial` is the head.
-  Existing tables: `users`, `sessions`, `worlds`, `assets`.
-- **Redis:** configured (`REDIS_URL`) but unused so far; adopted here for
-  idempotency short-caching and rate limiting.
-- **Models:** `User` (owner_id), `Asset` (owner_id, is_public, asset_type).
-  Marketplace items reference existing `assets` rows and/or avatar items.
-- **Content moderation:** `docs/architecture/content_moderation.md` defines
-  flag vocabulary, age gate, and moderation actions. Marketplace items and
-  listings must inherit and enforce these rules (see §7).
-- **Client:** Godot 4.6.2, minimal `main_menu.gd`; no economy UI yet.
-
-## 4. Key design decisions
-
-| Concern | Decision |
-|---|---|
-| Currency model | Single virtual currency **"Credits" (CR)**, integer units. One wallet row per user; no fractional amounts. |
-| Ledger | Append-only `transactions` table: signed `amount`, `balance_after`, `reference_type`/`reference_id`, unique `idempotency_key`. |
-| Concurrency | `SELECT ... FOR UPDATE` on the wallet row inside the mutation transaction; never read-modify-write from stale data. |
-| Payments | Pluggable `PaymentProvider` interface with a **no-op default** that simulates a confirmed payment for dev/testing (clearly flagged). Stripe/PayPal later. |
-| Marketplace items | `catalog_items` (what is sold) + `marketplace_listings` (a seller's offer with a price/status). One item can have multiple listings over time. |
-| Purchase flow | Atomic transaction: debit buyer → hold funds in escrow (`pending_escrow`) → grant item. Platform fee computed server-side. |
-| Escrow | Configurable hold window (default 72h) before `pending_escrow` becomes available seller earnings. Refunds during the window reverse the sale. |
-| Fees | Single configurable `MARKETPLACE_FEE_RATE` (default `0.30`). `seller_net = floor(price * (1 - fee_rate))`. |
-| Creator balance | `creator_balances` table: `available` (earned, payable), `pending` (inside an open payout request), `lifetime_earned`. Updated in the same transaction as the sale completion. |
-| Payouts | Pluggable `PayoutProvider.pay()` with a no-op default (simulated external ref). Minimum payout threshold, admin review for large payouts. |
-| Idempotency | Every money-moving request carries a client-generated `Idempotency-Key`; duplicate keys return the original result. |
-| Rate limiting | Redis token-bucket dependency reused from the social feature for purchase/listing/payout endpoints. |
-| Moderation | Listings enforce content flags + age gate; moderators can `delist`/`remove`; fraud/chargeback reversal is an audited admin action. |
-
-## 5. User stories
-
-### US-1 Currency & wallet
-As a player, I can see my Credit balance and transaction history, and the system
-credits/debits my wallet only through server-authoritative events.
-
-**Acceptance criteria**
-- Exactly one wallet per user, created lazily on first use.
-- Balance is always a non-negative integer; no operation can make it negative.
-- Every mutation appends an immutable ledger row with amount, resulting balance,
-  reference, and idempotency key.
-- Retrying a request with the same idempotency key does not double-apply.
-- `GET` endpoints expose current balance and paged transaction history.
-
-### US-2 Premium purchase (buy Credits)
-As a player, I can purchase Credits with real money and have them credited only
-after the payment is confirmed.
-
-**Acceptance criteria**
-- A purchase session is created through the payment provider (or the no-op
-  default) and is idempotent.
-- Credits are granted exactly once, only after a verified provider confirmation
-  (webhook/confirm endpoint), never on client claim.
-- Purchase amounts are bounded and server-defined; clients cannot pick arbitrary
-  prices.
-- Confirmation is idempotent and audited (provider reference recorded).
-
-### US-3 Marketplace listing (sell)
-As a creator, I can list a catalog item for sale at a Credit price and
-manage/remove my listings.
-
-**Acceptance criteria**
-- A listing references a valid `catalog_item` owned by the seller (or an
-  authorized seller).
-- Price is bounded (min/max) and set server-side; status transitions are
-  explicit (`active`, `sold`, `delisted`, `removed_by_moderation`).
-- Only the seller (or a moderator) can update/remove a listing.
-- Listings are searchable/filterable (item type, price range, owner).
-
-### US-4 Marketplace purchase (buy)
-As a player, I can buy a listed item. The purchase is atomic, holds funds in
-escrow, grants the item, and splits the payment between platform and seller.
-
-**Acceptance criteria**
-- A single transaction debits the buyer, holds funds in escrow, and grants the
-  item — no partial states on failure.
-- Platform fee and seller net are computed server-side from the configured rate.
-- After the escrow hold window, funds move from escrow to the seller's
-  available balance.
-- Refunds during the hold window reverse the sale and return funds to the buyer.
-- Concurrent purchases of a one-of-a-kind listing cannot both succeed.
-
-### US-5 Creator payouts
-As a creator, I can view my earned balance, request a payout, and track its
-status; admins can review and approve/reject payouts.
-
-**Acceptance criteria**
-- Available balance is derived only from completed (escrow-released) sales and
-  completed payouts; it never goes negative.
-- Payout requests are bounded (min threshold, max per period) and rate-limited.
-- Large payouts require admin review; all payout requests carry an audit trail
-  (requested by, reviewed by, provider reference, status).
-- The payout provider is called exactly once; idempotent on retry.
-
-### US-6 Godot client
-As a player, I can manage Credits, browse/buy/sell marketplace items, and manage
-payouts from the game UI.
-
-**Acceptance criteria**
-- An API client handles JWT auth, HTTP, and idempotency keys for all economy
-  calls.
-- Dedicated screens: wallet + transaction history, marketplace browse/buy,
-  sell-listing, and creator payout.
-- The client never computes balances, fees, or seller nets — it only displays
-  server responses.
-
-## 6. Task breakdown
-
-Right-sized to 1–3 files / one coherent piece of functionality each. Task IDs
-are sequential for dependency chaining.
-
-| # | Task | Story | Depends on |
-|---|------|-------|-----------|
-| 1 | Wallet & ledger models + Alembic migration (`wallets`, `transactions`) | US-1 | — |
-| 2 | Wallet service (atomic credit/debit, idempotency, locking) + wallet/transactions API | US-1 | 1 |
-| 3 | Premium purchase: `PaymentProvider` interface + purchase/confirm endpoints | US-2 | 1 |
-| 4 | Catalog item & listing models + migration (`catalog_items`, `marketplace_listings`, `creator_balances`) | US-3 | 1 |
-| 5 | Marketplace listing API (create/list/search/update/remove) | US-3 | 4 |
-| 6 | Marketplace purchase service + API (atomic escrow, fee split, item grant) | US-4 | 2, 4, 5 |
-| 7 | Creator payout request models + API (`payout_requests`) | US-5 | 2, 6 |
-| 8 | Payout admin review + `PayoutProvider` + audit | US-5 | 7 |
-| 9 | Marketplace moderation + content-flag/age-gate enforcement | cross-cutting | 5, 6 |
-| 10 | Godot economy API client (auth + HTTP + idempotency) | US-6 | 2 |
-| 11 | Godot wallet & transaction history UI | US-6 | 10 |
-| 12 | Godot marketplace browse/buy UI | US-6 | 6, 10 |
-| 13 | Godot selling & payout UI | US-6 | 5, 7, 10 |
-
-## 7. Phasing
-
-- **Phase 1 (currency + payments):** tasks 1–3. The foundation — ledger and
-  money movement must be rock-solid before anything spends Credits.
-- **Phase 2 (marketplace):** tasks 4–6. Listing and atomic purchase with escrow.
-- **Phase 3 (payouts):** tasks 7–8. Turn released escrow into creator payouts.
-- **Phase 4 (moderation):** task 9. Lock down the marketplace against mature
-  content and abuse.
-- **Phase 5 (client):** tasks 10–13, each landing after its backend dependency.
-
-## 8. Data model sketch
-
-```text
-wallets
-  id                bigint PK
-  user_id           int UNIQUE FK -> users.id
-  balance           bigint NOT NULL DEFAULT 0  CHECK (balance >= 0)
-  created_at        timestamptz
-  updated_at        timestamptz
-
-transactions        (append-only ledger)
-  id                bigint PK
-  wallet_id         bigint FK -> wallets.id
-  type              enum(credit_purchase, marketplace_purchase,
-                        marketplace_sale, escrow_release, payout,
-                        refund, admin_adjustment)
-  amount            bigint NOT NULL            (signed)
-  balance_after     bigint NOT NULL
-  reference_type    text                        (e.g. "purchase", "sale", "payout_request")
-  reference_id      text
-  idempotency_key   text UNIQUE
-  metadata_json     jsonb
-  created_at        timestamptz
-
-catalog_items
-  id                bigint PK
-  owner_id          int FK -> users.id
-  asset_id          int FK -> assets.id (nullable; null for non-asset virtual items)
-  item_type         enum(asset, avatar_item, experience_pass)
-  name              text
-  description       text
-  metadata_json     jsonb
-  created_at        timestamptz
-
-marketplace_listings
-  id                bigint PK
-  catalog_item_id   bigint FK -> catalog_items.id
-  seller_id         int FK -> users.id
-  price             bigint NOT NULL CHECK (price > 0)
-  status            enum(active, sold, delisted, removed_by_moderation)
-  created_at        timestamptz
-  updated_at        timestamptz
-
-purchases
-  id                bigint PK
-  listing_id        bigint FK -> marketplace_listings.id
-  buyer_id          int FK -> users.id
-  seller_id         int FK -> users.id
-  price             bigint NOT NULL
-  platform_fee      bigint NOT NULL
-  seller_net        bigint NOT NULL
-  status            enum(pending_escrow, completed, refunded, reversed)
-  escrow_hold_until timestamptz
-  created_at        timestamptz
-
-creator_balances
-  id                bigint PK
-  user_id           int UNIQUE FK -> users.id
-  available         bigint NOT NULL DEFAULT 0
-  pending           bigint NOT NULL DEFAULT 0
-  lifetime_earned   bigint NOT NULL DEFAULT 0
-  updated_at        timestamptz
-
-payout_requests
-  id                bigint PK
-  creator_id        int FK -> users.id
-  amount            bigint NOT NULL CHECK (amount > 0)
-  status            enum(pending, approved, paid, rejected)
-  external_ref      text
-  provider_ref      text
-  requested_by      int FK -> users.id
-  reviewed_by       int FK -> users.id (nullable)
-  reviewed_at       timestamptz
-  created_at        timestamptz
-```
-
-## 9. Security, anti-fraud & audit
-
-- **Server-authoritative balances/fees:** clients never compute totals; amounts
-  are validated server-side against bounds and the current listing.
-- **Row locking:** wallet and creator-balance mutations use `SELECT ... FOR
-  UPDATE` within one transaction.
-- **Idempotency:** every money-moving endpoint requires an `Idempotency-Key`;
-  duplicate keys return the stored original outcome.
-- **Rate limiting:** purchase, listing, and payout endpoints are token-bucket
-  rate-limited per user.
-- **Escrow & reversibility:** funds are not payable until the hold window
-  elapses; chargebacks/refunds reverse before release.
-- **Moderation:** listings carry the item's effective content flags; mature
-  items require age verification (per `content_moderation.md`); moderators can
-  `delist`/`remove` and trigger audited reversals.
-- **Audit:** the ledger plus `payout_requests` review fields form an append-only
-  audit trail for every movement of value.
-
-## 10. Out of scope for this feature
-
-- Real Stripe/PayPal/KYC integrations (provider interfaces leave the hooks; the
-  defaults are deterministic no-ops).
-- Subscriptions, recurring billing, or premium memberships.
-- Gift cards, promotional codes, or user-to-user Credit transfers.
-- Partial refunds, chargeback disputes, and seller tax/VAT handling.
-- In-world vending machines / scripted economy triggers (future, built on this
-  ledger via the scripting sandbox).