~x-ai/grok-latest → A (5:3)

A delivers lasting design: centralized room path encoding (`room_route_segment` / single `/r/:room_key` segment), shared `ROOM_SHORT_ID_LEN`, and external URL identity normalization (YouTube canonicalization, query sorting, case policy) wired through routes, HTML, and types. B is a precise, high-value correctness fix (zero-ratio votes no longer leave ghost items or voted_pairs), but it is a small localized guard move versus A’s foundational URL/routing model.