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/complete/fix-dashboard-read-state/ADVERSARIAL_BUG_REPORT.md

@@ -0,0 +1,12 @@
+# Adversarial Bug Report: fix-dashboard-read-state
+
+## Attack Vectors Tested
+1. **Corrupted .state file**: Empty file or garbage content — `_state_string_to_task_state()` returns `None`, falls back to artifact heuristic
+2. **Unknown phase in .state**: Returns `None`, falls back to artifacts — correct
+3. **Sub-state with multiple colons**: `code_review:awaiting_approval:extra` — `split(":")[0]` gives `code_review` — correct
+4. **Race condition**: `.state` file modified between read and use — not a concern for dashboard display (eventual consistency)
+
+## Findings
+No bugs found.
+
+## Verdict: PASS