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/plug-stale-task-hole/DOC_REVIEW.md

@@ -1,12 +0,0 @@
-# Doc Review — plug-stale-task-hole
-
-## Documentation Reviewed
-- IMPLEMENTATION.md (task folder)
-- SPEC.md
-- status.py --help or --touch documentation (if any)
-
-## Findings
-Documentation is accurate. The IMPLEMENTATION.md covers all changed files. The SPEC.md goal ("Add stale-task detection, --touch command, update guard plugin") is fully met. The `--touch` command is self-documenting via its usage in error messages.
-
-## Verdict
-Documentation is satisfactory. No changes needed.