Archive completed tasks, add cleanup commands, self-documenting dashboard UI

- Archive 79 completed framework-dev tasks from tasks/ -> tasks/complete/
- status.py: add --cleanup-done and --install-cleanup-schedule commands
- Add scripts/automaton-cleanup.sh for periodic task archiving
- Dashboard: rename 'Background' tab -> 'Agent', 'Cleanup' agent -> 'Completed Task Archiver', remove redundant group headers and pill badges, dim inactive agent placeholders
- .rules.md: add Self-Documenting UI Names rule
- New tests: test_cleanup_done.py, expanded test_app.py and test_task.py

tasks/complete/task-detail-modal/ADVERSARIAL_BUG_REPORT.md

@@ -0,0 +1,9 @@
+# Adversarial Bug Report: Centered Modal for Task Detail
+
+## Deep Review
+Modal uses fixed positioning with backdrop blur. Close on backdrop click checks `e.target === e.currentTarget`.
+
+## Potential Issues
+1. **Z-index stacking**: Modal overlay is z-index 100, help modal is z-index 200. If both open simultaneously, help modal overlays correctly.
+
+## Verdict: PASS