~x-ai/grok-latest → A (2:1)

Commit A removes the throwaway demo-counter path and replaces synchronous vote apply+log with a batched SettlementClient worker plus ranked_items_cached / warm_ranking_cache, so HTTP reads take read locks only and ranking is computed off the request path—a lasting concurrency and core-domain design. Commit B mainly pulls room short+slug into one path segment, centralizes room_route helpers, and adds YouTube/query URL normalization; useful but largely routing/identity polish versus A’s architectural write-path redesign.