openai/gpt-chat-latest → A (8:1)

Side A introduces a new `RouteContext` abstraction for HTML routing, exports it from `server/src/html/mod.rs`, and adds a detailed migration plan describing the architectural shift from string-based `CanonicalItemUrl` to structured `ItemId`. While much of the commit is planning documentation, the new routing layer creates a lasting extension point for centralizing URL generation, whereas Side B is almost entirely Clippy-driven cleanups, minor test fixes, and stylistic refactors with little effect on the project's design or functionality.