Why: branches merged into main had left their task cards open; backfill status and archive to prevent bookkeeping debt. Evidence: fix-artifact-version-dedupe.md(PR#382) — merges verified via git log --merges against origin/main. Impact: .task/*.md moved to .task/archive/ with status backfilled; no code or submodule change. Refs: task.sh close (card-autoclose-r1)