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/fix-stale-task-mtime-proxy/SPEC.md

@@ -0,0 +1,14 @@
+# Spec: fix-stale-task-mtime-proxy
+
+## Problem
+`scripts/status.py:965,1072` uses the `.state` file's mtime as a proxy for "last edit activity." But every `--transition` rewrites `.state`, resetting its mtime. A task that was transitioned 29 minutes ago appears "fresh" even though no editing happened. The `--same-session` check also gives false positives after any transition.
+
+## Fix
+Use a separate `.state.lastedit` timestamp file that is updated only when `--can-edit` returns ALLOWED (actual edit activity). Check `.state.lastedit` mtime instead of `.state` mtime for stale-task detection. If `.state.lastedit` doesn't exist, fall back to `.state` mtime (backward compat).
+
+## Acceptance Criteria
+- Transitioning a task does NOT reset the stale-task timer
+- Running `--can-edit` (and getting ALLOWED) DOES reset the timer
+- If `.state.lastedit` doesn't exist, falls back to `.state` mtime
+- Existing tests still pass
+- Add test verifying transition doesn't reset timer but can-edit does