~anthropic/claude-sonnet-latest → B (4:1)

Side B is a substantial, coherent architectural refactor: it replaces many ad-hoc REST endpoints with a unified batch RPC protocol, redesigns the reducer's scope/room model (Thread->Room, thread_id->room_id/thread_tag), and updates CLI, types, and all integration/grants tests to match — a real, consistently-applied design change with lasting structural value. Side A is a small, useful but narrow UI polish (vote-count badge, HUD unpin-via-POST bugfix) that touches a handful of files and one new helper/test, offering much less lasting architectural value than B's system-wide rework.