reset lock icon and status upon admin check failed

src/js/app.js

@@ -43,6 +43,9 @@ document.addEventListener('DOMContentLoaded', () => {
         }
       } catch (err) {
         console.warn('Admin check failed', err);
+        lockBtn.textContent = '🔒';
+        lockBtn.classList.add('locked');
+        lockBtn.title = 'Admin Login';
       }
     }