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-migrate-find-precedence/ADVERSARIAL_BUG_REPORT.md

@@ -1,11 +0,0 @@
-# Adversarial Bug Report: fix-migrate-find-precedence
-
-## Attack Vectors Tested
-1. **Path traversal via find**: No user input flows into the find command — paths are hardcoded
-2. **Escaped parentheses**: The `\(` and `\)` are correctly escaped for shell find
-3. **Empty directory list**: Not applicable — directories are hardcoded
-
-## Findings
-No bugs found. The fix is a static shell script change with no user-controlled input.
-
-## Verdict: PASS