Fix marked library loading error

- Remove type='module' from app.js script tag
- Allows access to global marked library loaded from CDN
- Fixes 'Uncaught ReferenceError: marked is not defined'

frontend/index.html

@@ -203,6 +203,6 @@
       </li>
     </template>
 
-    <script src="/app.js" type="module"></script>
+    <script src="/app.js"></script>
   </body>
 </html>