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/additive-extension-model/ADVERSARIAL_BUG_REPORT.md

@@ -1,11 +0,0 @@
-# Adversarial Bug Report: Additive Extension Model
-
-## Deep Review
-The global-first read order in orchestrate.md is correct. The extension loading order (after global for prompts/contracts, before global for scripts) makes sense — scripts need pre-processing hooks.
-
-## Potential Issues
-1. **Extension conflict**: If two extensions define the same file, the later one silently wins. No merge logic exists. This is by design (additive overrides), but could confuse users.
-
-2. **Script ordering**: Extensions loaded before global scripts (`pre-processing`). If a global script evolves and the extension was written for an older version, behavior could break silently.
-
-## Verdict: PASS — no security or logic flaws.