~x-ai/grok-latest → A (3:1)

A lands lasting architecture: a concrete RouteContext API (item_href, thread/garden/room URLs, ThreadNav interop) plus a phased ItemId migration plan that defines how identity and hrefs should evolve. B mainly improves local DX (cargo-watch fixture, persistent fixture-data/, preferred port) and removes a bit of room-page UI chrome—useful, but not structural product design.