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/fix-can-edit-path-prefix/SPEC.md

@@ -1,30 +0,0 @@
-# Spec: fix-can-edit-path-prefix
-
-## Problem
-`--can-edit` and `--scope-check` in `scripts/status.py` use `str(file_path).startswith(proj_str)` to verify a file is within the project directory. String `startswith` matches sibling directories: `/home/user/project-evil/file.py` matches prefix `/home/user/project`. This allows editing files outside the project boundary.
-
-Affected locations:
-- `scripts/status.py:951` (`--can-edit --project --file`)
-- `scripts/status.py:1004` (`--can-edit --task --file`, framework case)
-- `scripts/status.py:1010` (`--can-edit --task --file`, regular project case)
-- `scripts/status.py:1047` (`--scope-check`)
-- `scripts/status.py:1052` (`--scope-check`, framework check)
-
-## Fix
-Append a trailing path separator to the prefix before comparison:
-```python
-str(file_path).startswith(proj_str + os.sep)
-```
-Or use `Path.relative_to()` which correctly resolves path boundaries:
-```python
-try:
-    file_path.relative_to(project_dir.resolve())
-except ValueError:
-    # out of scope
-```
-
-## Acceptance Criteria
-- A file in `/home/user/project-evil/` is correctly rejected as out-of-scope when project is `/home/user/project`
-- A file in `/home/user/project/subdir/` is correctly accepted as in-scope
-- Both framework and regular project cases work
-- Add a test in `tests/test_status.py` covering the sibling-directory edge case