Fix syntax error in App.tsx: Restore missing useMemo declaration

App.tsx

@@ -497,6 +497,7 @@ const App: React.FC = () => {
   // Determine which dataset to use for velocity calculation based on top50Mode
 
   // Combine Sales & Ads Data dynamically based on current filters
+  const combinedAdsData = useMemo(() => {
     return mergeSalesAndAdsData(filteredData, filteredAdsData, globalAsinMetadata, trafficData, velocityMap);
   }, [filteredData, filteredAdsData, globalAsinMetadata, trafficData, velocityMap]);