Fix #1428 - Update Browser Tab Title When Notebook is Renamed (#1496)

* Updates to edit-app.tsx to resolve #1428

* fix: update browser tab title on notebook rename, prioritize app title. Fixes #1428

---------

Co-authored-by: victg <123119434+statistron@users.noreply.github.com>

frontend/src/core/edit-app.tsx

@@ -115,9 +115,11 @@ export const EditApp: React.FC<AppProps> = ({ userConfig, appConfig }) => {
       }
     });
 
-    return sendRename(name)
+      return sendRename(name)
       .then(() => {
         setFilename(name);
+         // Set document title: app_title takes precedence, then filename, then default
+        document.title = appConfig.app_title || name || "Untitled Notebook"; 
         return name;
       })
       .catch((error) => {
@@ -126,6 +128,12 @@ export const EditApp: React.FC<AppProps> = ({ userConfig, appConfig }) => {
       });
   });
 
+  // Update document title whenever filename or app_title changes 
+  useEffect(() => {
+    // Set document title: app_title takes precedence, then filename, then default
+    document.title = appConfig.app_title || filename || "Untitled Notebook"; 
+  }, [appConfig.app_title, filename]);
+
   const cells = notebookCells(notebook);
   const cellIds = cells.map((cell) => cell.id);
   const codes = cells.map((cell) => cell.code);