fix: session stability improvements

- Fix docker client initialization bug in app.py (context manager was closing client)
- Add restart_session() method to preserve session IDs during container restarts
- Add 60-second startup grace period before health checking new sessions
- Fix _stop_container and _get_container_info to use docker_service API consistently
- Disable mDNS in Dockerfile to prevent Bonjour service name conflicts
- Remove old container before restart to free port bindings

docker-compose.yml

@@ -30,6 +30,8 @@ services:
       # Host configuration
       - DOCKER_HOST_IP=${DOCKER_HOST_IP:-host.docker.internal}
       - DOCKER_TLS_PORT=${DOCKER_TLS_PORT:-2376}
+      # Disable database storage (use in-memory)
+      - USE_DATABASE_STORAGE=false
     networks:
       - lovdata-network
     restart: unless-stopped