env variables handling

index.html

@@ -154,6 +154,9 @@
         </div>
     </div>
       
+    <!-- Load environment configuration first -->
+    <script src="/config.env.js"></script>
+    
     <!-- Main application script -->
     <script type="module" src="/js/app.js"></script>
     <script>
@@ -214,7 +217,7 @@
                     let backendUrl;
                     try {
                         const configModule = await import('/js/config.js');
-                        backendUrl = configModule.BACKEND_URL;
+                        backendUrl = configModule.getBackendUrl();
                     } catch (error) {
                         output.textContent = 'Failed to load backend URL. Please check configuration.\n';
                         return;