feat: vendor Vue 3 and Bootstrap JS locally

Remove CDN dependencies to ensure the app works without internet access.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/index.html

@@ -731,8 +731,8 @@
       </div>
     </div>
 
-    <script src="https://unpkg.com/vue@3/dist/vue.global.prod.js"></script>
+    <script src="/app/vue.global.prod.js"></script>
-    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/js/bootstrap.bundle.min.js"></script>
+    <script src="/app/bootstrap.bundle.min.js"></script>
     <script src="/app/app.js" defer></script>
   </body>
   </html>