Why: 11 merged branches had left their task cards open (bookkeeping debt found on 2026-09-30); closure was manual and never triggered, so card status rotted after each merge.
Evidence: dogfood run of `task.sh close --fold` closed and archived the 11 cards (previous commit); temp-repo matrix 33/33 PASS covering detection, pending-branch idempotence, dirty/no-fold refusals, post-merge auto-close on merge-type pulls, worktree guard, and the full lifecycle (closure PR merge archives cards on main).
Impact: scripts/task.sh (+close, precheck [cards] report, finish-tail trigger), scripts/hooks/post-merge (new), Makefile (+task-close target, setup chmod), AGENTS.md rule; archive fixes correct PR links missed by the first dogfood run; no module or gitlink change.
Refs: task card feature/card-autoclose-r1
Why: branches merged into main had left their task cards open; backfill status and archive to prevent bookkeeping debt.
Evidence: delivery-mechanism.md(PR#unknown) feature-adopt-draft9.md(PR#unknown) feature-core-cards-commands-r1.md(PR#unknown) feature-gate-hardening.md(PR#unknown) feature-hardening-batch.md(PR#unknown) feature-pin-config-surface.md(PR#unknown) feature-pin-documents-lessons.md(PR#unknown) feature-tool-adaptation-standard.md(PR#unknown) feature-ui-foundation-r0.md(PR#unknown) feature-zcode-hooks.md(PR#unknown) fix-empty-list-json.md(PR#unknown) — 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)
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