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/pre-existing-fixes/DOC_REVIEW.md

@@ -1,13 +0,0 @@
-# Doc Review: Pre-existing Fixes
-
-## Review Summary
-
-All documentation and code comments are accurate.
-
-## Checklist
-- [x] `upgrade.sh` comments and error messages are clear
-- [x] `_infer_state_from_artifacts` docstring unchanged (function has no docstring — relies on code clarity)
-- [x] `cmd_validate_folder` error message for corrupted state is clear and actionable
-- [x] No stale references to removed behavior (no || true, no `.git/hooks` assumption)
-- [x] Tests are well-documented with descriptive names
-- [x] IMPLEMENTATION.md accurately describes all changes