Greptile Summary

This PR adds two regex patterns to the timeout error-pattern list in failover-matches.ts so that AbortError / stream-abort messages (e.g., "The operation was aborted", "stream closed") are correctly classified as reason=timeout instead of falling through to reason=unknown during model failover. Test coverage is added for all common message variants.

• /\boperation was aborted\b/i — maps Node.js/undici AbortError messages to timeout
• /\bstream (?:was )?(?:closed|aborted)\b/i — maps stream abort/close messages to timeout
• Both patterns use \b word boundaries to avoid partial-word false matches (e.g., "downstream closed" will not match)
• classifyFailoverReason calls isTimeoutErrorMessage late in its priority chain (after billing/auth/server-error checks), so higher-priority classifiers are unaffected
• Tests use expectTimeoutFailoverSamples, which validates isTimeoutErrorMessage, classifyFailoverReason, and isFailoverErrorMessage — thorough for the scope of the change

Confidence Score: 5/5

Safe to merge — minimal, targeted change with no logic regressions or false-positive risk from the new patterns.

Both new regex patterns are well-bounded by \b word anchors, follow the established convention in the file, and are exercised by comprehensive new test cases. The priority ordering in classifyFailoverReason ensures higher-specificity classifiers (billing, auth, server errors) still take precedence. No P0 or P1 findings were identified.

No files require special attention.

_{Reviews (1): Last reviewed commit: "failover: classify AbortError and stream..." | Re-trigger Greptile}

Merged via squash.

• Prepared head SHA: d8412f27e6d91bb53a244b964adbb3d99ec77956
• Merge commit: d9a7ffe003195ea8bd8e3b6f00dae557a895d9ad

Thanks @yelog!