fix: use processed image blob from modal for backend submission

Critical fix: modal processes image and returns blob, but AIOnboarding
was not actually using that blob. Now properly calls setExtractedImageBlob()
so confirmSingleItem sends the processed image to backend.

Before: Backend received original image, applied original AI crop/rotation
After: Backend receives processed image (already cropped/rotated by user)

Now the saved image matches exactly what user sees after adjusting.

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

frontend/components/AIOnboarding.tsx

@@ -34,6 +34,8 @@ export default function AIOnboarding({ onCancel, onComplete, categories, invento
     fileInputRef,
     existingTypes,
     existingBoxes,
+    extractedImageBlob,
+    setExtractedImageBlob,
     startLiveCamera,
     stopLiveCamera,
     captureSnapshot,
@@ -81,27 +83,17 @@ export default function AIOnboarding({ onCancel, onComplete, categories, invento
           user_adjusted: true
         }
       };
+      setExtractedItems(updatedItems);
 
-      // If modal processed and returned image blob, use that instead of original
+      // If modal processed and returned image blob, update the hook's state
+      // so confirmSingleItem uses the processed blob instead of original
       if (adjustments.imageBlob) {
-        // Convert blob to base64 for extracted_image_bytes
-        const reader = new FileReader();
-        reader.onload = () => {
-          const base64 = (reader.result as string).split(',')[1];
-          updatedItems[index].extractedImageBlob = adjustments.imageBlob;
-          updatedItems[index]._base64ImageData = base64;
-          setExtractedItems(updatedItems);
-          hookConfirmSingleItem(index);
-        };
-        reader.readAsDataURL(adjustments.imageBlob);
-      } else {
-        setExtractedItems(updatedItems);
-        hookConfirmSingleItem(index);
+        setExtractedImageBlob(adjustments.imageBlob);
       }
-    } else {
-      hookConfirmSingleItem(index);
     }
 
+    // Always call confirm, even without adjustments
+    hookConfirmSingleItem(index);
     setShowImageAdjustment(false);
     setAdjustingItemIndex(null);
     setPendingItemData(null);