openai/gpt-chat-latest → A (4:1)

Side A performs a substantial architectural migration from string-based `CanonicalItemUrl` keys to a structural `ItemId` type across the reducer, ranking, routing, RPC, HTML, and tests, while extracting shared normalization into `item_wire.rs`. This establishes a stronger identity model and cleaner APIs (for example `RouteContext`/`garden_item_href` and typed map keys) that affects core project design, whereas Side B is a targeted improvement to pair-selection heuristics and adds tests for better vote scheduling but is confined to one subsystem.