feat(review): wire review.auto_merge_summary into the unified comment (#4147)

[JSONbored]

Closes #4147.

Summary

buildAutoMergeSummaryCollapsible (src/review/unified-comment.ts:229, #2051) was a pure, unit-tested render primitive with zero real callers — setting review.auto_merge_summary in .gittensory.yml had no visible effect, unlike every other opt-in render toggle (review.changed_files_summary, review.effort_score, ...), which all flow through resolveReviewPromptOverrides into a real src/queue/processors.ts call site.

• Added autoMergeSummary to resolveReviewPromptOverrides (src/signals/focus-manifest.ts) — deterministic, no-AI, exact same shape as changedFilesSummary/effortScore.
• Threaded autoMergeSummaryEnabledForReview through src/queue/processors.ts the same way its siblings are threaded, resolved unconditionally (must render even when the AI review pass itself is skipped).
• Wired the collapsible into unified-comment-bridge.ts's UnifiedCommentBridgeArgs/buildUnifiedCommentBody extraCollapsibles chain — rendered right after manifest validation, ahead of the structural/visual collapsibles, since it's decision-relevant content.
• The four signals (ciGreen/gatePassing/mergeableClean/linkedIssueValid) reuse the SAME ciState/mergeStateLabel/gate-conclusion/pr.linkedIssues facts this pass already resolves for the readiness chip and gate verdict — no extra fetch. gatePassing mirrors the gate's own "no hard blocker" definition (conclusion === "success"); linkedIssueValid mirrors missing_linked_issue's own "has at least one linked issue reference" check.

Test plan

• npx tsc --noEmit — clean
• Full unit + integration suite: 687 files / 13,710 tests passing
• npm run docs:drift-check, npm run manifest:drift-check, npm run engine-parity:drift-check — all pass
• npm audit --audit-level=moderate — 0 vulnerabilities
• New tests: resolveReviewPromptOverrides's autoMergeSummary field (parse + default-off), buildUnifiedCommentBody renders/omits the collapsible correctly, and a full webhook → processJob → posted-comment e2e test asserting all four condition marks render correctly from a real fixture (CI passed, gate success, mergeable_state: clean, a linked issue in the PR body)

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.22%. Comparing base (9277537) to head (5ce9d0d).
⚠️ Report is 12 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4817   +/-   ##
=======================================
  Coverage   94.22%   94.22%           
=======================================
  Files         441      441           
  Lines       38745    38750    +5     
  Branches    14106    14109    +3     
=======================================
+ Hits        36508    36513    +5     
  Misses       1577     1577           
  Partials      660      660           

Files with missing lines	Coverage Δ
src/queue/processors.ts	95.71% <100.00%> (+<0.01%)	⬆️
src/review/unified-comment-bridge.ts	99.57% <100.00%> (+<0.01%)	⬆️
src/signals/focus-manifest.ts	99.64% <100.00%> (ø)

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.