fix: properly apply image adjustment overrides to AI-detected values

Fixed two critical issues:
1. Adjustments now properly override image_processing values
2. State updates explicitly ensure extractedItems are modified before confirm

Changes:
- handleImageAdjustmentConfirm now updates extractedItems state
- Adjustments properly stored in image_processing (rotation_degrees, crop_bounds)
- user_adjusted flag added to mark user-modified values
- Backend will use adjusted values instead of AI detection

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/components/AIOnboarding.tsx

@@ -63,12 +63,29 @@ export default function AIOnboarding({ onCancel, onComplete, categories, invento
   const handleImageAdjustmentConfirm = async (adjustments: { rotation: number; cropBounds: { x: number; y: number; width: number; height: number } } | null) => {
     if (!pendingItemData) return;
 
-    const { index, data } = pendingItemData;
+    const { index } = pendingItemData;
 
-    if (adjustments) {
-      data.image_adjustments = adjustments;
+    if (adjustments && extractedItems[index]) {
+      // Override AI-detected values with user adjustments
+      const updatedItems = [...extractedItems];
+      updatedItems[index] = {
+        ...updatedItems[index],
+        image_processing: {
+          ...updatedItems[index].image_processing,
+          rotation_degrees: adjustments.rotation,
+          crop_bounds: {
+            x: Math.round(adjustments.cropBounds.x),
+            y: Math.round(adjustments.cropBounds.y),
+            width: Math.round(adjustments.cropBounds.width),
+            height: Math.round(adjustments.cropBounds.height)
+          },
+          user_adjusted: true
+        }
+      };
+      setExtractedItems(updatedItems);
     }
 
+    // Now call the hook's confirm with the updated data
     hookConfirmSingleItem(index);
     setShowImageAdjustment(false);
     setAdjustingItemIndex(null);