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/complete/fix-stale-task-mtime-proxy/CODE_REVIEW.md

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+# Code Review: fix-stale-task-mtime-proxy
+
+## Reviewed Files
+- `scripts/status.py` (`_get_edit_timestamp()`, `_touch_lastedit()`, `cmd_can_edit()`, `cmd_same_session()`, `cmd_touch()`, `NON_ARTIFACT_FILES`)
+
+## Changes
+1. Added `.state.lastedit` file as the stale-task timer source
+2. `_touch_lastedit()` called on ALLOWED `--can-edit` responses
+3. `_get_edit_timestamp()` reads `.state.lastedit` with fallback to `.state` mtime
+4. Added staleness check to single-task `--can-edit --task` path
+5. `--touch` now touches `.state.lastedit` instead of `.state`
+
+## Analysis
+- **Correctness**: Using `.state.lastedit` (touched on actual edit activity) is a better proxy for staleness than `.state` mtime (which only reflects phase transitions)
+- **Backward compatibility**: Falls back to `.state` mtime when `.state.lastedit` doesn't exist
+- **Non-artifact**: `.state.lastedit` correctly added to `NON_ARTIFACT_FILES` to avoid being treated as a phase artifact
+- **Single-task path**: Adding staleness check to `--can-edit --task` makes enforcement consistent across both code paths
+- **`--touch` command**: Updated to touch `.state.lastedit` — consistent with the new activity tracking model
+
+## Verdict: PASS
+
+The fix is well-structured, maintains backward compatibility, and correctly addresses the mtime proxy issue. Tests cover creation, staleness detection, and fallback behavior.