feat: implement issue #2174 — Remove a PR from the merge queue when the fleet withdraws its last approval (reviews are only checked when a PR joins the queue)

Merged
DO
15d ago
+744-5

Problem

Remove a PR from the merge queue when the fleet withdraws its last approval (reviews are only checked when a PR joins the queue)

From the issue: Maintainer decision (2026-10-10): when the fleet withdraws an approval from a PR that is in the merge queue, the PR must be removed from the queue. Without this, withdrawing an approval no longer stops a merge.

Risk

Medium — changes GitHub Actions workflow behavior, which is exercised only post-merge; verify via the affected workflow runs.

Test plan

Tests added/updated: tests/test_merge_queue_dequeue.bats. Verification: bash scripts/dev-lead-lint.sh (shellcheck --severity=warning) ran pre-commit; the bats suite runs in CI.

Rollback

Revert this PR. No non-revertible side effects (no tags, migrations, or external state).

Monitoring

Watch the affected workflow run(s) in the Actions tab and this PR's Lint check for regressions.

Closes #2174