stop_call() now calls close_now() on the stored transport handle before killing the tokio runtime. This sends a QUIC CONNECTION_CLOSE frame so the relay's recv loop breaks immediately, triggering leave() + RoomUpdate broadcast. Previously the runtime was killed first, so transport.close() never ran and the relay kept stale participants until idle timeout. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>