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/fix-cat3-audit-paths/ADVERSARIAL_BUG_REPORT.md

@@ -1,18 +0,0 @@
-# Adversarial Bug Report: fix-cat3-audit-paths
-
-## Summary
-Adversarial review of the Category 3 audit path fix. No additional bugs found.
-
-## Bugs Found
-No bugs found.
-
-## Analysis
-- **Race conditions**: `_audit_category3` reads git diff state at a point in time. No concurrent modification risk since it's a read-only audit.
-- **Path traversal**: The check uses `Path(changed_file).parts` which splits on path separators — no traversal bypass possible.
-- **Edge case — nested subtasks**: `.automaton/tasks/parent/subtasks/child/file` has `parts[2]` = `parent`, which is in `task_names` (subtasks are listed as `parent` in `_all_task_dirs`). Correctly excluded.
-- **Edge case — empty task_names**: If `tasks` is empty, `task_names` is empty, and no file matches — all files flagged as unauthorized. This is correct behavior (no tasks = no authorized edits).
-
-## Score
-0
-
-ADVERSARIAL_BUG_FIND_COMPLETE