~x-ai/grok-latest → B (1:3)

B re-enables core multi-room HTML UI (ThreadNav abstraction, room index/thread/post/expand routes with ACL checks), browser session cookies + login/logout, and web ingest posting—foundational product surface. A is a useful but narrower incremental feature (optional pool param and next-pair scoping on an already-working vote path) with less architectural weight.