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/spec-in-detail/SPEC.md

@@ -1,19 +0,0 @@
-# SPEC: Display SPEC.md Content in Task Detail Panel
-
-## Overview
-
-The task detail panel shows verdict and bug report content but not the task's SPEC.md. Users need to see the specification when reviewing a task.
-
-## Changes
-
-- Add `spec_content` field to API responses (`_serve_tasks`, `_serve_task`)
-- Display SPEC.md content in the detail panel under a "Specification" section
-
-## Acceptance Criteria
-
-- [ ] SPEC.md content appears in detail panel
-- [ ] API serves `spec_content` for all tasks
-
-## VERDICT
-
-PASS — implemented in commit 01d8451