Inspector: live data updates under interactive selections

src/app/components/ChartBuilderModal.test.tsx

@@ -25,7 +25,12 @@ vi.mock('../services/chart-renderer', () => {
   }
   return {
     renderSpec: vi.fn(() =>
-      Promise.resolve({ destroy() {}, resize() {}, inspectData: () => null }),
+      Promise.resolve({
+        destroy() {},
+        resize() {},
+        inspectData: () => null,
+        onDataChange: () => () => {},
+      }),
     ),
     ChartTooLargeError,
   };