Move convoy check to run after verifyCommitOnMain succeeds, before the
cleanup_status switch. This ensures convoys can close when tracked work
is merged, even if polecat cleanup is blocked (has_uncommitted, etc.).
Previously the convoy check only ran after successful nuke, meaning
blocked polecats would prevent convoy completion detection.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>