perf: Redis pub/sub, PgBouncer, optimistic UI for high concurrency

- Add Redis 7 for pub/sub (lobby + chat real-time), rate limiting, caching
- Replace SSE DB polling with Redis pub/sub (lobby: instant approval, chat: instant delivery)
- Add PgBouncer (transaction mode, 500 client → 25 pool connections)
- Chat SSE stream via Redis pub/sub instead of 3s polling
- Optimistic UI in ChatPanel (messages appear before server confirms)
- Redis-based rate limiter (works across multiple app replicas)
- Prisma query optimization (select only needed fields)
- Chat message cache in Redis (10s TTL)
- Docker Compose: add redis, pgbouncer services with healthchecks
- Production: resource limits, 2 app replicas behind Traefik
- Update CLAUDE.md, README.md, .env.example, setup.sh

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -6,9 +6,14 @@ services:
     depends_on:
       postgres:
         condition: service_healthy
+      redis:
+        condition: service_healthy
+      pgbouncer:
+        condition: service_healthy
     env_file: .env
     environment:
-      DATABASE_URL: postgresql://postgres:${POSTGRES_PASSWORD:-postgres}@postgres:5432/liveserver
+      DATABASE_URL: postgresql://postgres:${POSTGRES_PASSWORD:-postgres}@pgbouncer:6432/liveserver
+      REDIS_URL: redis://redis:6379
     restart: unless-stopped
 
   postgres:
@@ -36,6 +41,34 @@ services:
       - minio_data:/data
     restart: unless-stopped
 
+  redis:
+    image: redis:7-alpine
+    command: redis-server --maxmemory 256mb --maxmemory-policy allkeys-lru --save ""
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+    restart: unless-stopped
+
+  pgbouncer:
+    image: edoburu/pgbouncer:latest
+    depends_on:
+      postgres:
+        condition: service_healthy
+    environment:
+      DATABASE_URL: postgresql://postgres:${POSTGRES_PASSWORD:-postgres}@postgres:5432/liveserver
+      POOL_MODE: transaction
+      MAX_CLIENT_CONN: 500
+      DEFAULT_POOL_SIZE: 25
+      MIN_POOL_SIZE: 5
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -h 127.0.0.1 -p 6432"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+    restart: unless-stopped
+
   ai-agent:
     build: ./ai-agent
     depends_on:
@@ -43,7 +76,7 @@ services:
         condition: service_healthy
     env_file: .env
     environment:
-      DATABASE_URL: postgresql://postgres:${POSTGRES_PASSWORD:-postgres}@postgres:5432/liveserver
+      DATABASE_URL: postgresql://postgres:${POSTGRES_PASSWORD:-postgres}@pgbouncer:6432/liveserver
     restart: unless-stopped
 
 volumes: