docs: streamline README and update SESSION_CONTEXT, archive outdated docs

- Streamline README.md from 645 to 365 lines (43% reduction)
- Remove duplicate content with other documentation files
- Focus README on quick start, features overview, and links to detailed docs
- Update SESSION_CONTEXT.md with recent changes (342/342 tests, matching runs audit)
- Archive outdated documentation:
  - CONTEXT.md (duplicated in README)
  - QUICKSTART.md (mentions mock auth, outdated)
  - QUICK_TEST.md (outdated)
- Keep SESSION_CONTEXT.md active for context restoration

docs/SESSION_CONTEXT.md

@@ -15,9 +15,9 @@
 
 ## Current Status
 
-**Phase:** MVP Complete - Ready for Production Deployment
-**Tests:** 285/286 backend tests passing - 99.7% (73% coverage)
-**Next Goal:** Infrastructure setup (server, domain, SSL)
+**Phase:** MVP Complete - Production Ready
+**Tests:** 342/342 backend tests passing - 100% ✅ (72.5% coverage)
+**Recent Work:** Matching runs audit, ratings & stats system, comprehensive test suite
 
 ### Core Features (All Implemented)
 - JWT authentication with email verification (AWS SES)
@@ -27,6 +27,10 @@
 - Recording matching system with 3-tier account system (BASIC/SUPPORTER/COMFORT)
 - Fairness algorithm (karma tracking: recordingsDone vs recordingsReceived)
 - Dual buffer system (prep before + rest after dancing)
+- Matching runs audit with origin_run_id tracking
+- Incremental matching (preserves accepted/completed suggestions)
+- Scheduler integration (automated matching with cron)
+- Atomic stats updates with race condition prevention
 - Clickable usernames with @ prefix, country flags
 - Matches & ratings API
 - QR code event check-in
@@ -49,16 +53,26 @@
 │   ├── hooks/               # useWebRTC.js
 │   └── constants/           # MATCH_STATUS, SUGGESTION_STATUS, etc.
 ├── backend/src/
-│   ├── routes/              # API endpoints
+│   ├── routes/              # API endpoints (events.js, matches.js, admin.js)
 │   ├── controllers/         # Business logic
 │   ├── services/            # matching.js (auto-matching algorithm)
 │   ├── socket/              # Socket.IO handlers
 │   ├── constants/           # Status constants
-│   └── __tests__/           # Jest tests
+│   └── __tests__/           # Jest tests (342 tests - 100% passing)
+│       ├── matching-algorithm.test.js      # 19 tests
+│       ├── ratings-stats-flow.test.js      # 9 tests
+│       ├── matching-runs-audit.test.js     # 6 tests
+│       ├── matching-incremental.test.js    # 5 tests
+│       └── socket.test.js                  # 12 tests
 └── docs/
-    ├── TODO.md              # Current tasks & security audit
+    ├── SESSION_CONTEXT.md   # This file - quick context
+    ├── TODO.md              # Current tasks & roadmap
     ├── ARCHITECTURE.md      # Technical details
-    └── archive/COMPLETED.md # Historical reference
+    ├── DEPLOYMENT.md        # Deployment guide
+    ├── MONITORING.md        # Operations guide
+    ├── TESTING_MATCHING_RATINGS.md  # Comprehensive test documentation (45 tests)
+    ├── WEBRTC_TESTING_GUIDE.md      # WebRTC testing guide
+    └── archive/             # Archived documentation
 ```
 
 ---
@@ -72,21 +86,58 @@ Key models:
 - `event_participants` - User-event relationship, competitorNumber, recorderOptOut, `accountTierOverride`
 - `divisions` / `competition_types` / `event_user_heats` - Competition system
 - `matches` - User pairings with CUID slugs
-- `ratings` - 1-5 stars, comments
-- `recording_suggestions` - Auto-matching results with collision detection
+- `ratings` - 1-5 stars, comments, `statsApplied` flag
+- `recording_suggestions` - Auto-matching results with collision detection, `originRunId` tracking
+- `matching_runs` - Audit trail (manual/scheduler, status, stats)
 - `chat_rooms` / `messages` - Real-time chat persistence
 
 ---
 
+## Recent Changes (Last 2 Days)
+
+### Matching Runs Audit System
+- **File:** `backend/src/__tests__/matching-runs-audit.test.js` (6 tests)
+- **Features:**
+  - origin_run_id assignment and tracking
+  - Sequential runs create separate audit records
+  - Accepted suggestions preserve origin_run_id across re-runs
+  - Admin endpoints with filtering (onlyAssigned, includeNotFound)
+  - Manual vs scheduler trigger differentiation
+
+### Ratings & Stats Integration
+- **File:** `backend/src/__tests__/ratings-stats-flow.test.js` (9 tests)
+- **Features:**
+  - Atomic stats updates (recordingsDone, recordingsReceived)
+  - Race condition prevention with `statsApplied` flag
+  - Source filtering (only auto matches update stats)
+  - Idempotency (double-rating prevention)
+  - E2E double-rating completion flow
+
+### Documentation
+- **Updated:** README.md with current test statistics (342/342)
+- **New:** docs/TESTING_MATCHING_RATINGS.md (comprehensive 45-test overview)
+- **Archived:** Outdated quick start guides
+
+---
+
 ## Quick Commands
 
 ```bash
 # Start development
-docker compose up --build
+docker compose --profile dev up
 
-# Run backend tests
+# Run all backend tests
 docker compose exec backend npm test
 
+# Run specific test suite
+docker compose exec backend npm test -- matching-runs-audit.test.js
+
+# Coverage report
+docker compose exec backend npm run test:coverage
+
+# Admin CLI
+docker compose exec backend npm run cli -- users:list --limit 20
+
 # Access
 # Frontend: http://localhost:8080
 # API: http://localhost:8080/api
@@ -117,6 +168,11 @@ ACCOUNT_TIER: BASIC | SUPPORTER | COMFORT
 // Tier fairness penalties
 FAIRNESS_SUPPORTER_PENALTY: 10
 FAIRNESS_COMFORT_PENALTY: 50
+
+// Matching config
+MAX_RECORDINGS_PER_PERSON: 3
+PREP_BUFFER_MINUTES: 30
+REST_BUFFER_MINUTES: 60
 ```
 
 ---
@@ -131,12 +187,38 @@ FAIRNESS_COMFORT_PENALTY: 50
 
 ---
 
+## Test Coverage Summary
+
+**Total:** 342/342 tests passing (100% ✅)
+
+- **Matching Algorithm:** 19 tests (TC1-TC19)
+  - Fundamentals, collision detection, limits, fairness, edge cases
+- **Ratings & Stats:** 9 tests
+  - Atomic updates, race prevention, idempotency
+- **Matching Runs Audit:** 6 tests
+  - origin_run_id tracking, sequential runs, filtering
+- **Incremental Matching:** 5 tests
+- **Recording Stats Integration:** 6 tests
+- **WebRTC Signaling:** 12 tests
+- **Socket.IO:** 12 tests
+- **API Routes:** Full CRUD coverage (auth, events, matches, dashboard)
+
+**Code Coverage:**
+- matching.js: 94.71% statements, 91.5% branches
+- routes/matches.js: 76.11% statements
+- routes/events.js: 78.2% statements
+
+---
+
 ## For More Details
 
-- `docs/TODO.md` - Security audit, future improvements
+- `docs/TODO.md` - Active tasks, security audit, future improvements
 - `docs/ARCHITECTURE.md` - Technical implementation details
+- `docs/TESTING_MATCHING_RATINGS.md` - Comprehensive test documentation
+- `docs/DEPLOYMENT.md` - Production deployment guide
+- `docs/MONITORING.md` - Operations and monitoring
 - `docs/archive/COMPLETED.md` - Full history of completed features
 
 ---
 
-**Last Updated:** 2025-11-29
+**Last Updated:** 2025-11-30