openai/gpt-chat-latest → A (3:2)

Side A adds a user-facing `room create` CLI command end-to-end, wiring it through the RPC, bearer authentication, documentation, and tests, while also simplifying the room model by removing the unused visibility field and replacing the room registry with a `HashSet` of room IDs. Side B is a solid internal refactor that strengthens type usage by returning `CanonicalItemUrl` from `resolve_item` and propagating typed URLs throughout ranking and validation code, but it is primarily a maintainability improvement rather than introducing new project capability.