Why: pipefail treated a recent merged-card match as a failed git log after grep exited early, hiding completed cards from precheck and task-close.
Evidence: A disposable long-history regression failed before the fix and passed after it; make test-governance passed 341 cases. Git history confirms PR #489/#488/#486 merge SHAs.
Impact: Detect merged cards reliably and archive only the three authorized trial cards; four unrelated eligible cards remain untouched.
Refs: Dev merge queue #518; Dev #489, #488, #486