Fix: Improve preview loading and error handling

src/hooks/useUnitPreferences.ts

@@ -15,7 +15,25 @@ export function useUnitPreferences() {
   const [loading, setLoading] = useState(true);
 
   useEffect(() => {
-    loadPreferences();
+    let mounted = true;
+    
+    const load = async () => {
+      try {
+        await loadPreferences();
+      } catch (error) {
+        console.error('Failed to load preferences:', error);
+      } finally {
+        if (mounted) {
+          setLoading(false);
+        }
+      }
+    };
+    
+    load();
+    
+    return () => {
+      mounted = false;
+    };
   }, [user]);
 
   const loadPreferences = async () => {
@@ -58,7 +76,15 @@ export function useUnitPreferences() {
 
   const autoDetectPreferences = useCallback(async () => {
     try {
-      const response = await supabase.functions.invoke('detect-location');
+      // Add timeout to prevent hanging
+      const timeoutPromise = new Promise((_, reject) => 
+        setTimeout(() => reject(new Error('Location detection timeout')), 5000)
+      );
+      
+      const response = await Promise.race([
+        supabase.functions.invoke('detect-location'),
+        timeoutPromise
+      ]) as any;
       
       if (response.data && response.data.measurementSystem) {
         const newPreferences: UnitPreferences = {