~x-ai/grok-latest → A (2:1)

A lands a core domain redesign: a real `ItemId` type (with wire split, parse/parent/display, serde) replaced `CanonicalItemUrl` through reducer maps, ranking, RPC, HTML routing, and tests—lasting structure rather than a string newtype. B adds important but narrower hardening (fail-closed `resolve_vote_actor`, mock-OAuth gate, Secure cookies, open-redirect checks, nav alias, durable rev pin); valuable security/UX, not the same system-wide foundation.