PR-fix attempt cap counts review comments, blocking multi-comment reviews before any attempt #1103

Problem

The PR-fix attempt cap from #1001 counts distinct evidence keys as attempts (src/lib/pr-fix-queue.ts, capExceeded = !isKnownEvidence && nextEvidenceKeys.length > maxPrFixAttempts()). Every inline review comment gets its own evidence key (review_comment:<repo>#<pr>:<id>), so one review with 5 or more inline comments exceeds the cap on first sight. The item goes BLOCKED/NEEDS_HUMAN before anything has worked it even once.

This happened on #1095. The PR-fix history shows it was born blocked: enqueue at 11:46:26 with lane NEEDS_HUMAN and note "Bounded at 6 attempts (PR_FIX_MAX_ATTEMPTS=5)", then "Bounded at 7 attempts" at 11:46:28. That is one CHANGES_REQUESTED review with 6 inline comments plus the review itself. The item is still at generation 1, and no fix-pr CoderRun was ever created for it. The AI reviewer routinely posts this many inline findings, so any substantive review on a coder PR bypasses the fix loop entirely.

Expected

The cap should bound fix attempts (dispatched coder runs), not the number of findings in one review. A single review, however many comments it carries, is one round of feedback.

Suggested fix

Count attempts from something that advances once per attempt. Options:

• the item's work generation, which already bumps on every fresh dispatchable attempt (feat(queue): expose PR-fix work generations #1044)
• distinct attemptHeadSha / head SHAs the item was queued against
• distinct review: / check_run: keys only, excluding review_comment:

Generation is the closest match to "attempts" and is already maintained. Whichever is chosen, PR_FIX_MAX_ATTEMPTS semantics and the note text in enqueuePrFixItem should say what is counted.

Add a regression test to src/lib/pr-fix-queue.test.ts: a first enqueue of one review with 6+ review_comment keys (all at the same head) must stay QUEUED in lane NORMAL.

Files

• src/lib/pr-fix-queue.ts (enqueuePrFixItem, maxPrFixAttempts)
• src/lib/pr-fix-queue.test.ts