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/cleanup-cruft/IMPLEMENTATION.md

@@ -1,24 +0,0 @@
-# Implementation: Clean Up Framework Cruft
-
-## Summary
-- R1: Deleted `debug_root.py` (development diagnostic script at framework root)
-- R2: Removed stale `dashboard = ["inotify>=0.2"]` optional dependency from `pyproject.toml`
-- R3: Deleted empty `automaton/dashboard/ui/widgets/` directory
-- R4: Fixed `config.md` line 18: changed "via `free`" to "via `/proc/meminfo` or `sysctl`"
-- R5: Documented `scripts/dashboard.sh` convenience wrapper in `README.md` Dashboard section
-- R6: Fixed `_find_tasks_dir()` — removed tautological condition, changed return type to `Path`, updated callers
-- R7: Removed `sys.path.insert(0, ...)` hack from `__main__.py`
-
-## Changes
-- Deleted: `debug_root.py`, `automaton/dashboard/ui/widgets/`
-- `pyproject.toml`: Removed `dashboard = ["inotify>=0.2"]`
-- `config.md`: Fixed RAM detection description
-- `README.md`: Added dashboard.sh convenience wrapper documentation
-- `automaton/dashboard/ui/app.py`: `_find_tasks_dir()` now returns `Path` (not `Path | None`), removed tautology
-- `automaton/dashboard/__main__.py`: Removed `sys.path.insert` hack
-
-## Test Results
-134 passed in 0.08s
-
-## Blockers
-None