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/implement-task/SPEC.md

@@ -1,15 +0,0 @@
-# Contract: Dashboard Implementation
-
-## Goal
-Implement the interactive terminal dashboard for the automaton framework.
-
-## Acceptance Criteria
-- [x] Board view works
-- [x] Statistics view works
-- [x] Timeline view works
-- [x] Filter bar works
-- [x] Search bar works
-- [x] Auto-refresh works
-
-## Stop Condition
-CONTRACT_MET