openai/gpt-chat-latest → A (4:1)

Side A adds a complete, focused capability: a new authenticated `RoomList` RPC, CLI `room list` command, shared response types, and thorough integration tests that verify per-user room isolation and grant behavior. Side B mixes substantial authentication work with a massive removal of the in-tree `durable` crate in favor of an external Git dependency, making much of the patch repository restructuring rather than durable project functionality, so the lasting value visible in this commit is harder to attribute and less self-contained.