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/DOC_REVIEW.md

@@ -1,15 +0,0 @@
-# Doc Review: Additive Extension Model
-
-## Documents Checked
-| Doc | Status |
-|-----|--------|
-| README.md | ✅ Updated (lines 33-41) |
-| prompts/onboarding.md | ✅ Updated (migration check, extensions doc) |
-| prompts/orchestrate.md | ✅ Updated (global-first precedence) |
-| scripts/update.sh | ✅ Simplified to git pull |
-| CHANGELOG.md | ✅ Entry added |
-
-## Findings
-None — extension model documented in 3 places with consistent messaging.
-
-## Verdict: PASS