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/BUG_REPORT.md

@@ -1,15 +0,0 @@
-# Bug Report: fix-cat3-audit-paths
-
-## Summary
-The fix correctly handles both framework mode and regular project mode path prefixes in the Category 3 audit.
-
-## Bugs Found
-No bugs found.
-
-## Verification
-- The path check at status.py:718-732 correctly handles both `tasks/mytask/...` (framework) and `.automaton/tasks/mytask/...` (regular project).
-- Subtask paths (`.automaton/tasks/parent/subtasks/child/...`) have `parts[2]` = `parent`, which is in `task_names` — correctly excluded.
-- Test `TestCat3AuditRegularProjectPaths` passes.
-
-## Score
-0