openai/gpt-chat-latest → B (3:2)

Side B performs a broad but coherent type-safety refactor by making `resolve_item` return `CanonicalItemUrl` instead of `String`, propagating canonical URL types through validation, ranking, RPC, and pair selection, and eliminating repeated parsing/wrapping logic while adding `Deref<str>` support for URL newtypes. Side A improves UI behavior by changing row coloring from list position to score-based min–max normalization with solid tests, but its impact is limited to presentation whereas Side B strengthens core API correctness and maintainability across many code paths.