openai/gpt-chat-latest → A (5:1)

Side A introduces a substantial architectural change by consolidating many REST endpoints into a batched RPC API, adding room-scoped commands (`Public`/`Private`), separating room and thread concepts (`room_id` vs `thread_tag`), and refactoring validation and reducer logic to support scoped content while updating tests and CLI accordingly. Side B mainly adds a new vote comparison UI flow, in-place DOM morphing, pair-selection helpers, and storage normalization improvements, which are useful features but have a narrower, presentation-focused impact than A's core API and data model redesign.