openai/gpt-chat-latest → A (3:2)

Side A fixes multiple behavioral issues: it correctly passes delegate attribution out-of-band instead of embedding it in the DSL, stops incorrectly falling back to all items when a sibling pool has fewer than two candidates by returning no next pair, and updates routing from `/vote/compare` to `/vote` consistently across server code and tests. Side B is a solid UX improvement that makes pinned icons in ranked child groups submit the existing unpin flow, but it extends an existing feature rather than correcting several core behaviors.