~x-ai/grok-latest → A (2:1)

A lands an end-to-end room-create path (CLI + RPC) and a lasting domain cleanup: drops ThreadVisibility/RoomState, makes rooms a HashSet of private ids, and tightens create/audit call sites across server, types, and tests. B is a real but narrower fix—Reddit children attach via apply_entity_under_parent without ensure_path side effects, and unranked rows use stored titles—plus test wiring, so less structural impact than A’s model and feature surface.