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/task-detail-modal/SPEC.md

@@ -1,24 +0,0 @@
-# SPEC: Convert Task Detail Panel to Centered Modal
-
-## Overview
-
-The sliding side panel (380px wide) is too narrow to read SPEC.md, verdicts, and other task content. Replace it with a centered modal overlay that uses the full screen width.
-
-## Changes
-
-- Replace `.detail-panel` fixed sidebar with `.modal-overlay` + `.modal-panel`
-- Wrapped detail panel HTML in a modal overlay container
-- Added backdrop click to close
-- Updated JS references from `detail-panel` to `detail-overlay`
-
-## Acceptance Criteria
-
-- [ ] Modal is centered with 720px max width, 85vh max height
-- [ ] Content is scrollable within the modal
-- [ ] Clicking backdrop closes the modal
-- [ ] Escape key closes the modal
-- [ ] Existing functionality (review buttons, artifact display) is preserved
-
-## VERDICT
-
-PASS — implemented in commit 6630577