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/artifact-badges/IMPLEMENTATION.md

@@ -1,20 +0,0 @@
-# Implementation: Artifact Badges on Task Cards
-
-## Summary
-
-Added compact artifact badge chips to task cards for tasks with pending review or changes requested status.
-
-## Changes Made
-
-### `dashboard.js`
-- Added `ARTIFACT_LABELS` mapping from state to artifact filename
-- `renderTaskCard()` shows artifact badges when review status is `pending` or `changes_requested`
-- Approved/completed tasks do not show artifact badges
-
-### `styles.css`
-- `.task-card-artifacts` — flex container for badge row
-- `.artifact-badge` — monospace chip style
-
-## Files Modified
-- `automaton/dashboard/html/dashboard.js` — artifact badge rendering
-- `automaton/dashboard/html/styles.css` — badge styles