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/ADVERSARIAL_BUG_REPORT.md

@@ -0,0 +1,14 @@
+# Adversarial Bug Report: Pre-existing Fixes
+
+## Deep Bugs Found: 0
+
+No code paths introduced regressions. Verified:
+- `_infer_state_from_artifacts` logic trace correct for all artifact combinations
+- `cmd_validate_folder` now properly catches corrupted `.state` files
+- `upgrade.sh` will now fail visibly instead of silently succeeding
+- `git rev-parse --git-dir` works for worktrees (returns `.git/worktrees/<name>`)
+- Edge case: bare repos (`--git-dir` returns the repo path itself) — hooks directory is `<repo>/hooks/` which `mkdir -p` handles correctly
+
+## Pre-existing Issues Still Not In Scope
+- Lock timeout parsing in multi-agent mode is case-sensitive
+- Audit Category 3 (git modification check) is stubbed