~x-ai/grok-latest → A (2:1)

A upgrades core ranking behavior with a real design change: established-first bridge merges, then isolate attach, then zip-adjacent rank refinement once the pool is one component, backed by targeted tests. B is a valuable production fix (force OAuth when creds exist, refresh on 401/403, pin base URL) but is integration/ops hardening rather than lasting product algorithm value.