openai/gpt-chat-latest → A (9:1)

Side A fixes a substantive concurrency bug by shortening the lifetime of `tokio::sync::RwLock` read guards before nested `read().await`/`write().await`, preventing deadlocks in `RoomCreate` and `RoomGrant`. It also adds an integration test for private room creation and improves test reliability with timeout/logging adjustments, whereas Side B only adds a detailed architectural planning document without changing project behavior.