openai/gpt-chat-latest → A (3:2)

Side A fixes multiple functional issues: it passes delegate attribution out-of-band instead of embedding it in DSL text, prevents an incorrect fallback to all items when the sibling pool has fewer than two candidates by returning no next pair, and simplifies the voting flow by removing the swap button while consistently renaming the route from `/vote/compare` to `/vote` across server code and tests. Side B improves UI coloring by basing gradients on normalized vote scores within a group and adds solid tests, but this is primarily a presentation enhancement rather than a correctness or workflow fix.