openai/gpt-chat-latest → A (4:1)

Side A adds a complete user-facing capability: a new RoomList RPC, CLI `room list` subcommand, shared request/response types, server implementation that filters rooms by authenticated grants, and integration tests verifying per-user isolation and grant behavior. Side B is primarily architectural refactoring to introduce a `/ui` dispatch path, shared web handler helpers, and form-template infrastructure, but it does not deliver a comparably complete, validated feature and lacks end-to-end coverage in this patch.