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

tests/test_task.py

@@ -134,6 +134,19 @@ def test_discover_tasks(tmp_path: Path) -> None:
     assert tasks[1].state == TaskState.RESEARCH
 
 
+def test_discover_tasks_skips_complete_container(tmp_path: Path) -> None:
+    _make_task(tmp_path, "active", {"SPEC.md": "# Spec"})
+    complete = tmp_path / "complete"
+    complete.mkdir()
+    (complete / "done-task").mkdir()
+    (complete / "done-task" / "VERDICT.md").write_text("## Status: PASS")
+    (complete / "REVIEW.md").write_text("# Review\n- **Status**: approved")
+
+    tasks = discover_tasks(tmp_path)
+    assert len(tasks) == 1
+    assert tasks[0].name == "active"
+
+
 def test_discover_tasks_skips_subtasks_root(tmp_path: Path) -> None:
     parent = tmp_path / "parent"
     parent.mkdir()