fix: show item save confirmation with image before closing

- Add savingIndex state to track saving operation
- Display success overlay with saved image for 1.5 seconds
- Show item name in confirmation message
- Prevents modal from closing immediately after save

Fixes user complaint about image disappearing too quickly without confirmation

frontend/hooks/useAIExtraction.ts

@@ -11,6 +11,7 @@ export function useAIExtraction(inventory: Item[], onComplete: (itemData: any) =
   const [mode, setMode] = useState<'item' | 'box'>('item');
   const [isLive, setIsLive] = useState(false);
   const [extractedImageBlob, setExtractedImageBlob] = useState<Blob | null>(null);
+  const [savingIndex, setSavingIndex] = useState<number | null>(null);
 
   const videoRef = useRef<HTMLVideoElement>(null);
   const canvasRef = useRef<HTMLCanvasElement>(null);
@@ -157,17 +158,24 @@ export function useAIExtraction(inventory: Item[], onComplete: (itemData: any) =
         imageProcessing: data.image_processing
       })
     };
+
+    // Show success briefly before closing
+    setSavingIndex(index);
     onComplete(newItem);
 
-    if (extractedItems.length > 1) {
-      const remaining = [...extractedItems];
-      remaining.splice(index, 1);
-      setExtractedItems(remaining);
-      setEditingIndex(null);
-    } else {
-      setExtractedItems([]);
-      setEditingIndex(null);
-    }
+    // Reset UI after brief delay so user sees the success
+    setTimeout(() => {
+      if (extractedItems.length > 1) {
+        const remaining = [...extractedItems];
+        remaining.splice(index, 1);
+        setExtractedItems(remaining);
+        setEditingIndex(null);
+      } else {
+        setExtractedItems([]);
+        setEditingIndex(null);
+      }
+      setSavingIndex(null);
+    }, 1500);
   };
 
   const confirmAllItems = async () => {
@@ -255,6 +263,7 @@ export function useAIExtraction(inventory: Item[], onComplete: (itemData: any) =
     existingBoxes,
     extractedImageBlob,
     setExtractedImageBlob,
+    savingIndex,
     startLiveCamera,
     stopLiveCamera,
     captureSnapshot,