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/project-migration/SPEC.md

@@ -1,34 +0,0 @@
-# SPEC: Project Migration Script for Additive Extension Model
-
-## Overview
-
-After switching to the additive extension model, existing projects have stale copies of framework files in their `{project}/.automaton/` directories. These need to be cleaned up.
-
-## Context
-
-Under the old model, framework files (prompts, contracts, scripts) were copied into the project's `.automaton/`. Under the new model, the project should only contain `.agent.md`, `.rules.md`, and optionally an `extensions/` directory. Everything else comes from `~/.automaton/`.
-
-## Changes
-
-### 1. `scripts/migrate-project.sh`
-
-Script that takes a project path and:
-1. Scans `{project}/.automaton/` for files that now live in `~/.automaton/`
-2. For each matching file:
-   - **Identical to global** → delete (framework provides them)
-   - **Different from global** → move to `.automaton/extensions/`
-3. Preserves `.agent.md` and `.rules.md` as-is
-4. Reports what was deleted, moved, and kept
-
-### 2. `prompts/onboarding.md`
-
-Add a section at the top that checks if migration is needed:
-- If project has prompt/contract/script copies in `.automaton/`, offer to run migration
-
-## Acceptance Criteria
-
-- [ ] `scripts/migrate-project.sh` exists and is executable
-- [ ] Script correctly identifies identical vs customized files
-- [ ] Customized files are moved to `extensions/`, not deleted
-- [ ] `.agent.md` and `.rules.md` are never touched
-- [ ] Onboarding detects stale projects and offers migration