fix test

Author: ktaletsk

ui-tests/tests/jupyter_projspec.spec.ts

@@ -5,6 +5,9 @@ test('should activate and register the projspec sidebar panel', async ({
 }) => {
   // The extension registers a panel with id "projspec-panel" in the right sidebar.
   // Verify the panel tab is present, which confirms the extension activated.
-  const panelTab = page.locator('#tab-bar-projspec-panel');
+  // In JupyterLab 4 (Lumino 2), sidebar tabs use data-id attributes, not HTML id.
+  const panelTab = page.locator(
+    '.lm-TabBar.jp-SideBar .lm-TabBar-tab[data-id="projspec-panel"]'
+  );
   await expect(panelTab).toHaveCount(1);
 });