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/changelog/IMPLEMENTATION.md

@@ -1,24 +0,0 @@
-# Implementation: Changelog and Release Notes Process
-
-## Summary
-
-Created a root-level CHANGELOG.md and codified the changelog update process in `.rules.md`.
-
-## Changes Made
-
-### `CHANGELOG.md`
-Created at `~/.automaton/CHANGELOG.md` with:
-- `[unreleased]` header
-- `### Added` and `### Changed` sections
-- Entries for all completed tasks (additive-extension-model, framework-self-enforcement, changelog, framework-audit)
-
-### `.rules.md`
-Added "Changelog" section:
-- When a task reaches Resolution (VERDICT.md written), append an entry to CHANGELOG.md
-- Format: `- description (#task-name)` under the appropriate section
-
-## Files Created
-- `CHANGELOG.md` — root-level changelog
-
-## Files Modified
-- `.rules.md` — added changelog rules