~x-ai/grok-latest → B (1:4)

B fixes a real tokio RwLock deadlock in RoomCreate/RoomGrant by dropping read guards before nested lock acquires, plus an integration test and test harness fixes (log-pipe deadlock, HTTP timeouts, auth username assertions). A only improves local DX (cargo-watch fixture, persistent fixture-data, port preference) and a small UI trim—useful but not production-correctness.