~x-ai/grok-latest → A (2:1)

Commit A removes disposable demo-counter scaffolding and introduces a real settlement worker (batched vote append + ranking recompute, warm cache, read-path ranked_items_cached, write→read lock narrowing)—lasting core architecture for the vote/rank loop. Commit B mainly wires theme cookies through layout/auth and room-scoped API URL helpers; useful correctness and UX, but more surface plumbing than A’s concurrency and ranking design.