codex smoke: api fallback after codex exec

[Pigbibi]

Temporary smoke test for CodexAuditBridge after treating non-quota codex exec failures as API-fallback eligible.

Expected mode: review_only; no source repository changes requested.

[quantcrossrepoautomation]

Codex Audit

Codex service failed with exit code 1 and was classified as unknown_failure, so provider=auto correctly attempted API fallback instead of treating it as service auth/config failure.

API fallback was configured but all API reviewers failed because both configured API credentials were rejected by the providers.

• OpenAI fallback failed: authentication error (invalid_api_key).
• Anthropic Claude fallback failed: authentication error (invalid x-api-key).

No files were pushed. Rotate/update the relevant GitHub Actions secrets before retrying this smoke.

[Pigbibi]

Smoke run confirmed Codex exec failures now reach API fallback. This issue was superseded by #110 to verify sanitized fallback comments.