Add `style` to allowed commit-lint prefixes

[fullsend-ai-retro]

What happened

PR #1178 included commit 2a0be48 with message style: ruff-format unicode_posttool.py. The merge queue CI run (26467180105) failed because the .gitlint CT1 rule only allows feat, fix, refactor, docs, test, chore, ci, perf — not style. The PR was ultimately merged directly by waynesun09, bypassing the failed merge queue check.

What could go better

The style prefix is part of the Conventional Commits spec and is commonly used for formatting-only changes (exactly what happened here — running ruff-format). The repo's CLAUDE.md and CONTRIBUTING.md reference Conventional Commits, but the gitlint config is stricter than the spec. This creates a gap where valid conventional commits fail CI. High confidence this is a real issue — the evidence is direct (CI failure log shows the exact rule violation).

Proposed change

Update .gitlint (or equivalent commit-lint config) to add style to the CT1 allowed prefixes list. Also consider adding build and revert which are other standard Conventional Commits types that may be missing. The full standard set is: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert.

Validation criteria

After the change, style: prefixed commits should pass the commit-lint CI job. Verify by checking that the next merge queue run with a style: commit does not fail on CT1.

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Generated by retro agent from #1178

[fullsend-ai-triage]

Triage Summary

Severity: Medium — valid commits are rejected by CI, forcing merge queue bypasses.

Problem: The .gitlint CT1 rule allows only a subset of the Conventional Commits spec (feat, fix, refactor, docs, test, chore, ci, perf). The style, build, and revert types — all part of the standard spec — are missing. This caused a real CI failure on PR #1178 when a style: prefixed commit was used for a ruff-format change.

Root cause: The allowed types list in .gitlint and the types table in CONTRIBUTING.md were set to a subset of the full Conventional Commits specification.

Recommended fix:

1. Add style, build, and revert to the types list in .gitlint under [contrib-title-conventional-commits]
2. Add corresponding rows to the commit types table in CONTRIBUTING.md with purpose and release-note visibility
3. Run make lint to confirm the change passes

Proposed test case:

# For each new type, verify gitlint accepts the commit message:
echo 'style: format code with ruff' | gitlint
echo 'build: update go module dependencies' | gitlint
echo 'revert: undo feature X' | gitlint

# Verify invalid prefixes still fail:
echo 'foo: invalid prefix' | gitlint  # should fail CT1

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Labels: CI config bug affecting the commit-lint pipeline, suitable for autonomous resolution.