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/plug-stale-task-hole/IMPLEMENTATION.md

@@ -1,22 +0,0 @@
-# Plug Stale Task Hole Implementation
-
-## Summary
-Added stale-task detection, `--touch` command in status.py, and updated guard plugins to block edits on stale tasks.
-
-## Changes
-
-### scripts/status.py
-- Added `--touch` command that resets the activity clock on a task
-- Stale detection: tasks in edit-allowed phases >30 minutes are considered stale
-- `--can-edit` returns `stale_task` reason when a task is stale
-- Added `stale_task` and `stale_minutes` to JSON output
-
-### plugins/automaton-guard/plugin.ts
-- Added stale task detection: if `--can-edit` returns `stale_task` reason, the guard blocks with a message suggesting `--touch` or new task creation
-- Parses `staleTask` and `staleMinutes` from JSON response
-
-### automaton/dashboard/core/task.py
-- Added stale task awareness in the dashboard
-
-### tests/test_task.py
-- Added tests for stale task detection and touch functionality