Backport release/v6.6: Tolerate failed Codex review executions

[seidroid]

Backport of #3807 to release/v6.6.

[cursor]

PR Summary

Low Risk
CI-only change to error handling around the Codex review step; no application, auth, or production runtime impact.

Overview
Makes the PR → Codex → Slack workflow keep going when the Codex CLI exits non-zero, instead of failing the whole job under set -euo pipefail.

Both Codex paths (embedded pr.diff and large-diff URL fallback) now run inside if ! ...; then handlers that log "Codex review failed; publishing fallback review." The large-diff branch also prints codex.log to stderr for debugging. Unchanged behavior still applies when review.md is missing or empty: the step writes Codex produced no output. so later Slack upload steps can run.

Backport of #3807 onto release/v6.6.

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Aug 18, 2026, 6:11 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.12%. Comparing base (851cc6e) to head (c7299b2).

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v6.6    #3951      +/-   ##
================================================
- Coverage         58.78%   58.12%   -0.66%     
================================================
  Files              2220     2151      -69     
  Lines            183137   174998    -8139     
================================================
- Hits             107649   101722    -5927     
+ Misses            65781    64235    -1546     
+ Partials           9707     9041     -666     

Flag	Coverage Δ
sei-db	70.41% <ø> (?)
sei-db-state-db	?

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see 110 files with indirect coverage changes

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[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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[cursor]

Missing Codex failure log dump

Low Severity

The small-diff Codex failure handler redirects all output to codex.log but never prints it, unlike the large-diff handler which runs cat codex.log. Because failures are now non-fatal, the common path can succeed with only a generic message and no reason for the failure in the CI logs.

Additional Locations (1)

• .github/workflows/pr-to-slack-codex.yml#L134-L143

 

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