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/remove-file-system-watcher/IMPLEMENTATION.md

@@ -0,0 +1,17 @@
+# Implementation: Remove File System Watcher
+
+## Summary
+Removed the half-implemented `refresh.py` file system watcher module and updated the dashboard README to reflect the actual client-side polling refresh mechanism.
+
+## Files Changed
+- `automaton/dashboard/core/refresh.py` — deleted
+- `automaton/dashboard/README.md` — removed watcher from architecture diagram, fixed tree formatting
+
+## Verification
+- `automaton/dashboard/core/refresh.py` no longer exists.
+- `python -m automaton.dashboard` still starts and refreshes via JS polling.
+- `python -m pytest tests/` still passes.
+
+## Decisions
+- The dashboard uses client-side polling (`setInterval`) for auto-refresh.
+- No replacement watcher was implemented.