~anthropic/claude-sonnet-latest → B (3:1)

Side B removes dead/unused complexity (the never-really-used ThreadVisibility::Public branch, simplifying RoomState to a HashSet), adds a genuinely new CLI capability (`room create`) with corresponding RPC/reducer/timeline updates and test/doc updates across the stack. Side A is mostly UI polish (vote counts, HUD unpin button, CSS) plus doc tweaks—useful but narrower in scope and lasting impact than B's structural simplification and new feature wiring.