openai/gpt-chat-latest → A (4:1)

Side A introduces a new `RouteContext` abstraction in `server/src/html/routing.rs`, re-exports it, and documents a concrete migration plan toward structured `ItemId` and centralized route generation, creating a reusable architectural direction even though most call sites are not yet migrated. Side B mainly updates the GitHub Actions Node version, removes an npm upgrade step, and deletes a couple of obsolete tests, which is comparatively routine maintenance with less lasting impact on the codebase design.