fix: reorder hooks to resolve handleSync declaration order

frontend/app/page.tsx

@@ -61,6 +61,12 @@ export default function Home() {
   const [comparisonModal, setComparisonModal] = useState<{ show: boolean, newItem: any, existingItem: any, existingId: number | null }>({ show: false, newItem: null, existingItem: null, existingId: null });
   const [comparisonLoading, setComparisonLoading] = useState(false);
 
+  const { syncing, handleSync } = useSync({
+    isOnline,
+    currentUser,
+    onInventoryUpdate: setInventory
+  });
+
   const {
     mode,
     setMode,
@@ -106,12 +112,6 @@ export default function Home() {
     onInventoryUpdate: setInventory
   });
 
-  const { syncing, handleSync } = useSync({
-    isOnline,
-    currentUser,
-    onInventoryUpdate: setInventory
-  });
-
   useEffect(() => {
     if (!localStorage.getItem('inventory_token')) {
       window.location.href = '/login';
@@ -163,22 +163,6 @@ export default function Home() {
     }
   };
 
-  const handleSync = useCallback(async () => {
-    if (!isOnline || !currentUser) return;
-    setSyncing(true);
-    try {
-      const result = await syncOfflineOperations(currentUser.id);
-      if (result.success > 0) {
-        toast.success(`Synced ${result.success} operations!`);
-      }
-      await loadInventory();
-    } catch (error) {
-      console.error("Sync failed", error);
-    } finally {
-      setSyncing(false);
-    }
-  }, [isOnline, currentUser]);
-
   const handleOnboardingComplete = async (itemData: any) => {
     try {
       if (itemData.part_number) {