fix(review): scope draft-cycle counting to the author's own conversions

[JSONbored]

Summary

• Follow-up to fix(review): close repeated ready<->draft cycling as review evasion #3962 (merged before this fix landed -- gittensory-orb flagged a real defect after CI/mergeable state had already gone clean, and the gate merges owner PRs on that state regardless of the AI review's advisory blockers).
• The bug: draft_conversion_count incremented on EVERY converted_to_draft webhook regardless of actor, while enforcement only checked the actor at close-time. A maintainer's one-off draft toggle followed by the author's own first-ever (legitimate) conversion could reach count>=2 and wrongly close that first conversion as "repeated cycling."
• Fix: only increment the counter when the converter IS the PR's own author. Also moved the cheap reviewEvasionProtection/count checks ahead of the actuation-lock claim (a non-blocking nit from the same review) to avoid contending with the two sibling guards on repos that never enabled this feature.
• Added a regression test proving a maintainer-then-author conversion sequence is never enforced, and that the counter itself only reflects the author's own conversions.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• This PR is focused (single fix, no unrelated changes).
• This follows CONTRIBUTING.md.
• No open issue is linked -- direct owner follow-up fixing a defect found in review on fix(review): close repeated ready<->draft cycling as review evasion #3962.

Validation

• npm run typecheck
• Targeted test run: npx vitest run test/unit/queue.test.ts -t "repeated ready<->draft cycling|bumpPullRequestDraftConversionCount" -- 26/26 pass, including the new maintainer-then-author regression.
• 100% branch coverage on the changed lines (verified via lcov branch inspection); the one now-provably-unreachable defensive branch is marked with a justified v8 ignore comment.

Safety

• No secrets/private data exposed.
• No auth/CORS/session changes.
• No API/UI changes.

[loopover-orb]

Important

🟪🟪🟪🟪🟪🟪🟪🟪🟪🟪🟪🟪

🔍 Gittensory is reviewing…

AI analysis is in progress. This comment will update when the review is complete.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed · 🟪 Reviewing}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.70%. Comparing base (583e7b2) to head (3469661).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3979   +/-   ##
=======================================
  Coverage   93.70%   93.70%           
=======================================
  Files         373      373           
  Lines       35076    35076           
  Branches    12862    12863    +1     
=======================================
  Hits        32868    32868           
  Misses       1584     1584           
  Partials      624      624           

Files with missing lines	Coverage Δ
src/queue/processors.ts	94.71% <100.00%> (ø)

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