~x-ai/grok-latest → A (3:2)

Commit A adds lasting design: a composable `url_rules` engine/registry, scheme-bearing canonical ItemIds, smarter parent/breadcrumb rules, and real domain normalizers (Reddit + YouTube), not just renames. Commit B’s ItemId enum and CanonicalItemUrl removal improve type structure across reducer/RPC/HTML, but most of the diff is mechanical type propagation with similar string-backed keys and little new behavior.