openai/gpt-chat-latest → A (4:1)

Side A adds a substantive new capability by exposing private room creation through the CLI, wiring a new `room create` command to the existing RPC, improving user guidance, and simplifying the server model by removing the unused room visibility field and replacing the room registry with a `HashSet`. Side B mainly removes theme support and switches browsing to cleaner `/~/...` URLs with related routing and helper refactors, which is useful but largely a UI/navigation cleanup compared with the new end-to-end functionality delivered in Side A.