openai/gpt-chat-latest → A (4:1)

Side A makes substantive architectural improvements by introducing a settlement worker that batches vote persistence and ranking recomputation, adds cached ranking reads (`ranked_items_cached`) to avoid unnecessary recomputation under read locks, and warms the cache at startup. Although it also removes the demo counter UI, the lasting value comes from improving concurrency, performance, and vote processing, whereas Side B is primarily a refactor that relocates path and URL types into a shared `slug_types` module and updates call sites without substantially changing behavior.