chore: Remove unuseed variable

Co-authored-by: Copilot <[email protected]>

Author: toshimaru

src/assets/js/app.js

@@ -1,4 +1,4 @@
-document.addEventListener('DOMContentLoaded', (event) => {
+document.addEventListener('DOMContentLoaded', () => {
   anchors.options.visible = 'always';
   anchors.add();
 });