fix: upgrade command works without git connection for disconnected users

- Clone latest to .tmp/ directory instead of using git upstream
- Users stay completely disconnected from original repo
- Use .tmp/ instead of /tmp/ to hide from Obsidian
- Add user choice when local modifications detected
- Verify all files were addressed with checklist
- Clean up temp directory after upgrade
- Add .tmp/ to .gitignore

.gitignore

@@ -26,5 +26,8 @@ node_modules/
 .node_modules/
 pnpm-lock.yaml
 
+# Temporary directories
+.tmp/
+
 # Never commit real API keys
 *_API_KEY