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/CODE_REVIEW.md

@@ -1,12 +0,0 @@
-# Code Review: fix-cat3-audit-paths
-
-## Summary
-Fix is minimal and correct. Adds a second path check for `.automaton/tasks/` prefix to handle regular projects.
-
-## Findings
-- **Correctness**: The fix correctly handles both framework mode (`tasks/...`) and regular project mode (`.automaton/tasks/...`). The `if not is_in_task_folder` guard before the second check avoids redundant evaluation.
-- **Edge cases**: Subtask paths (`.automaton/tasks/parent/subtasks/child/...`) would have `parts[2]` = `parent`, which is in `task_names` (since `_all_task_dirs` includes subtasks with their parent name). This is correct — subtask files are also excluded from unauthorized.
-- **No regressions**: Existing framework-mode audit tests still pass.
-
-## Verdict
-APPROVED — no issues found.