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/artifact-badges/ADVERSARIAL_BUG_REPORT.md

@@ -1,9 +0,0 @@
-# Adversarial Bug Report: Artifact Badges on Task Cards
-
-## Deep Review
-ARTIFACT_LABELS mapping is static and matches COLUMNS. Badge rendering depends on review status, which is fetched from the API.
-
-## Potential Issues
-1. **XSS in artifact label**: ARTIFACT_LABELS values are hardcoded — no injection vector. Safe.
-
-## Verdict: PASS