~x-ai/grok-latest → B (1:3)

B fixes real indexing semantics (1-based optional fallback → 0-based invariant matching /t/tag/N), drops a silent unwrap_or(0) that could hide missing posts, aligns RPC/HTML/types, and locks behavior with integration asserts. A only introduces a missing GITHUB_API_BASE_URL default—necessary but a one-site config patch with no comparable design or test depth.