~x-ai/grok-latest → A (3:1)

Side A adds the end-to-end `room create` CLI path and simplifies the core domain (drop ThreadVisibility/RoomState, rooms as HashSet, RPC/tests/docs aligned), which is lasting product and model work. Side B only improves auth choose-username UX via fragment morph instead of redirects—valuable polish, but narrower and UI-local versus A’s feature plus structural cleanup.