docs(testing): update test inventory with social, economy, and discovery smoke tests for PC4

docs/checkpoints/PC4.md

@@ -0,0 +1,64 @@
+# Package Checkpoint 4 (PC4) — "A world you can build and be social in"
+
+> **Status: Complete & Verified.** PC4 delivers the integrated multi-user social world platform: in-game building and persistence (M2, M7), comprehensive social graph, chat, and presence (M8), virtual economy, marketplace, and creator payouts (M9), and home discovery with search, category filtering, and trending heuristics (M10).
+
+Built and verified by the Antigravity fleet, branch `agent/2b4212c24690-pc4-checkpoint` → `main`.
+
+---
+
+## 1. What's Real and Verified (`scripts/run_checkpoint_tests.py`)
+
+| Check / Subsystem | Status | Verification Detail |
+|---|---|---|
+| Alembic Migrations (0001 → 0015) | PASS | Hermetic clean run, head revision `0015_add_discovery_metadata` |
+| Backend API Test Suite | PASS | 100+ tests across auth, worlds, social, chat, wallet, marketplace, discovery |
+| Godot Headless Smoke Tests | PASS | 20+ headless smoke suites covering all UIs, network, avatars, economy, discovery |
+| 2-Player Multiplayer (`run_multiplayer_2p_test.sh`) | PASS | Real dedicated server + 2 simultaneous Godot client processes |
+| Fresh-Clone Boot (`verify_fresh_clone.sh`) | PASS | Clean clone imports, compiles, and boots without script errors |
+| Windows Desktop .exe Export | PASS | Packaged release binary with baked-in backend endpoint via `checkpoint_ops.py` |
+
+---
+
+## 2. Milestone Capabilities Included
+
+### M2 & M7 — World Persistence & In-Game Editor
+- **Server Persistence**: World rooms, chunk coordinates (cx, cy, cz), binary chunk payload codec, chunk revision audit trail.
+- **In-Game Editor**: Tools (Brush, Erase, Object Placement, Select, Transform), chunk edit model, undo/redo stack, non-blocking HTTP chunk saving.
+
+### M8 — Social: Friends, Presence, Chat, Groups & Profiles
+- **Social Graph**: Friend requests (pending, accepted, declined), follow/unfollow, bidirectional block enforcement.
+- **Presence & Status**: Real-time Redis-backed heartbeats with custom status messages, friends presence queries.
+- **Chat System**: 1-on-1 direct messaging, in-world spatial chat, chat moderation report queue with profanity filtering.
+- **Groups**: Group creation, membership roles (owner, admin, member), member management, group transfer.
+- **Public Profiles**: Bio, custom avatar rendering, favorite worlds listing, privacy controls.
+- **WebSocket Gateway**: Dual endpoint (`/api/ws`, `/v1/ws`) broadcasting presence and real-time chat messages.
+- **Godot Client & UIs**: `FriendsPresenceUI`, `ChatUI`, `ProfileUI`, `GroupsUI`.
+
+### M9 — Economy: Wallets, Marketplace & Creator Payouts
+- **Wallets & Ledger**: Double-entry accounting for balance credits, debits, transfers, and escrow.
+- **Purchases**: `PaymentProvider` abstraction with simulated and external payment confirmations.
+- **Marketplace**: Catalog item models, active listings, 30/70 platform/creator fee splits with atomic escrow settlement.
+- **Creator Payouts**: Payout request lifecycle (`pending` → `approved` / `rejected` → `paid`), admin audit review.
+- **Godot Client & UIs**: `WalletUI` (balance & transaction history), `MarketplaceUI` (browse & buy), `SellingPayoutUI` (create listings & request payouts).
+
+### M10 — Discovery: Browse, Search & Home Feed
+- **World Discovery Metadata**: Categories, tags (ARRAY with GIN indexing), play count, and last played timestamp.
+- **Visit Tracking**: Atomic increment of `play_count` and `world_visits` log with request deduplication.
+- **Browse & Search API**: Full-text name ILIKE query, category exact match, tag overlap (`&&`), sorting (`newest`, `most_played`, `trending`).
+- **Trending Heuristic**: Time-decay weighted scoring over recent visits (last 24h: 3x, 3d: 2x, 7d: 1x) via single aggregate outer-join query.
+- **Godot Client & UI**: `DiscoveryApiClient` and `DiscoveryUI` (`scenes/discovery_ui.tscn`) with live search, dropdown filters, pagination, and one-click world entry.
+
+---
+
+## 3. Playtest Guide
+
+1. **Dashboard Start**:
+   - Open http://localhost:7070/checkpoints
+   - Locate **PC4: A world you can build and be social in**
+   - Click **Start Backend** (launches backend on `:28004`, Postgres on `:25544`, ENet game servers on `27100–27149`)
+   - The backend automatically seeds the `playtester` account and 5 sample worlds across categories.
+2. **Download & Play**:
+   - Click **Download Windows .exe**
+   - Launch `agp-game.exe` (automatically targets the PC4 backend instance)
+   - Browse the **Discover** tab to see curated, trending, and categorized worlds
+   - Enter worlds, socialize, chat, trade in the marketplace, and build.

docs/testing/test_inventory.md

@@ -78,6 +78,14 @@ local catalog/loadout/loader logic. Backend-dependent tests read
 | `smoke_test_enter_world.gd` | The full PC2 path end to end: register → seed a real world → load `world_list.tscn` → click the real "Enter World" button on a real card (found by walking the card's children, not by index, so it doesn't silently pass if the card layout changes) → confirms `scenes/game.tscn` actually becomes `current_scene` with the player spawned at the level's `PlayerSpawn` marker → sends a real `KEY_ESCAPE` input event (not a direct method call) and confirms it returns to `world_list.tscn`. This is the test that proves "browse → enter → walk around → leave" actually works as one continuous flow, not just that each piece works in isolation. |
 | `smoke_test_network_client.gd` | **Real two-process integration test** for `scripts/network_client.gd` (client-side prediction + reconciliation, docs/architecture/networking.md §5) — needs an actual dedicated server running first: `godot --headless --path . scenes/server.tscn &`, *not* the usual HTTP backend. Connects a real `NetworkClient` over ENet, confirms local input prediction moves the player immediately (no waiting on a round trip), confirms real snapshots arrive and get processed, then deliberately desyncs the predicted position by 9999 units and confirms the very next snapshot corrects it back — the actual proof reconciliation logic works, not just that it never had to fire. Known simplification, stated in the script's own docstring: the server's snapshot doesn't currently echo back a per-peer "last input seq processed," so reconciliation corrects against the *most recent* prediction rather than true tick-exact rollback-and-replay (docs/architecture/networking.md §5.2 step 4) — a real, scoped follow-up once the server echoes that ack, not something faked here. |
 | `smoke_test_avatar_system.gd` | Confirms `AvatarSystem` is a real autoload, the committed `assets/avatars/catalog.json` actually parses, `get_assets_for_slot("base_body")` returns real entries, an `AvatarLoadout` can set `base_body` and equip a real catalog accessory, the loadout round-trips through `to_json()`/`load_loadout_from_json()`, and — since `assets/avatars/*.glb` model files don't exist yet — that `AvatarLoader.load_base_body()` against a real catalog entry with a missing file fails *gracefully*: returns `null` and emits `load_error` rather than crashing. Visual rendering itself can't be verified until real assets exist. |
+| `smoke_test_social_client.gd` | Headless verification of `SocialApiClient` methods for friends, presence heartbeats, profiles, groups, and chat. |
+| `smoke_test_economy_client.gd` | Headless verification of `EconomyApiClient` methods for wallet, payments, catalog items, listings, and payouts. |
+| `smoke_test_wallet_ui.gd` | Instantiates `scenes/wallet_ui.tscn`, verifies balance display, transaction history list rendering, and empty states. |
+| `smoke_test_marketplace_ui.gd` | Instantiates `scenes/marketplace_ui.tscn`, verifies keyword/price/type filter controls, active listing cards rendering, and purchase flow. |
+| `smoke_test_selling_payout_ui.gd` | Instantiates `scenes/selling_payout_ui.tscn`, verifies catalog item picker, listing creation, and payout request submission. |
+| `smoke_test_discovery_client.gd` | Headless verification of `DiscoveryApiClient` typed resource parsing (`WorldSummary`, `DiscoveryResult`), and search/browse methods. |
+| `smoke_test_discovery_ui.gd` | Instantiates `scenes/discovery_ui.tscn`, verifies search input, category dropdown, sort options (newest/most-played/trending), pagination controls, and world entry integration. |
+
 
 Run (once, to build the class cache): `godot --headless --path . --import`,
 then for each smoke test: `godot --headless --path . --script