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/pre-existing-fixes/VERDICT.md

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+# Verdict: pre-existing-fixes
+
+## Status: PASS
+**Completion Date**: 2026-06-15
+
+## Summary
+Fixed 4 pre-existing issues:
+1. `_infer_state_from_artifacts` heuristic: SPEC-only now correctly returns `research` instead of `bug_find`; IMPLEMENTATION-only returns `bug_find` (implement done → next phase)
+2. `cmd_validate_folder`: corrupted `.state` files now error instead of silently falling back to artifact inference
+3. `upgrade.sh`: removed `|| true` so upgrade failures are visible; added python3 availability check; uses `git rev-parse --git-dir` for hooks directory (supports worktrees)
+4. 6 new tests covering all fixes
+
+## Findings
+- All 206 tests pass
+- No regressions introduced
+- Heuristic fix aligns with existing `TestStateMachineAlignment` tests
+
+## Score
++10