fix: CRITICAL - remove double rotation (frontend + backend)

Root cause: Image was being rotated TWICE:
1. Frontend rotated it in the modal and sent processed blob
2. Backend rotated it AGAIN based on rotation_degrees

This double rotation made the image appear unrotated or distorted.

Solution: Remove frontend image processing entirely.
- Modal now sends ONLY the rotation value
- No imageBlob from modal (uses original)
- Backend receives original image + rotation value
- Backend applies rotation ONCE

Now image is rotated correctly by backend without duplication.

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

frontend/components/AIOnboarding.tsx

@@ -96,9 +96,12 @@ export default function AIOnboarding({ onCancel, onComplete, categories, invento
       // CRITICAL: Update state AND processed blob BEFORE calling hook
       setExtractedItems(updatedItems);
 
+      // DON'T replace image blob - modal no longer processes image
+      // Backend will apply rotation to original image
       if (adjustments.imageBlob) {
-        console.log('[Update] Setting extractedImageBlob to processed blob:', adjustments.imageBlob.size, 'bytes');
-        setExtractedImageBlob(adjustments.imageBlob);
+        console.log('[Update] Processed blob received but NOT using (backend will process)');
+      } else {
+        console.log('[Update] No imageBlob - using original, backend will apply rotation');
       }
 
       // CRITICAL: Call hook with UPDATED item, not old one

frontend/components/ImageAdjustmentModal.tsx

@@ -130,57 +130,21 @@ export function ImageAdjustmentModal({ imageUrl, onConfirm, onCancel }: ImageAdj
     console.log('[User] Rotation:', rotation, '°');
     console.log('[User] Use image flag:', useImage);
 
-    // Process image: apply rotation ONLY (no crop)
-    const processCanvas = document.createElement('canvas');
-    const ctx = processCanvas.getContext('2d');
-    if (!ctx) {
-      console.log('[ERROR] Could not get canvas context');
-      return;
-    }
-
+    // DON'T process image in frontend - let backend handle rotation
+    // Just send the rotation value, backend will apply it once
     const { width, height } = imageDimensions;
 
-    // Calculate canvas size needed to fit rotated image (prevent clipping)
-    const radians = (rotation * Math.PI) / 180;
-    const cos = Math.abs(Math.cos(radians));
-    const sin = Math.abs(Math.sin(radians));
-    const newWidth = Math.ceil(width * cos + height * sin);
-    const newHeight = Math.ceil(width * sin + height * cos);
+    console.log('[Decision] Sending rotation to backend for processing');
+    console.log('[Decision] NOT processing image in frontend (avoid double rotation)');
+    console.log('=== END DEBUG ===');
 
-    processCanvas.width = newWidth;
-    processCanvas.height = newHeight;
-
-    console.log('[Processing] Original dimensions:', width, 'x', height);
-    console.log('[Processing] Canvas size for rotation:', newWidth, 'x', newHeight);
-    console.log('[Processing] Applying rotation:', rotation, '°');
-
-    // Apply rotation around center of canvas
-    ctx.save();
-    ctx.translate(newWidth / 2, newHeight / 2);
-    ctx.rotate(radians);
-    ctx.drawImage(imageRef.current, -width / 2, -height / 2);
-    ctx.restore();
-
-    console.log('[Processing] Canvas draw complete');
-
-    // Convert to blob
-    processCanvas.toBlob((blob) => {
-      if (blob) {
-        console.log('[Result] Processed image blob size:', blob.size, 'bytes');
-        console.log('[Result] Blob type:', blob.type);
-        console.log('[Result] Final canvas size:', newWidth, 'x', newHeight);
-        console.log('=== END DEBUG ===');
-        // Return with new canvas bounds and rotation
-        onConfirm({
-          rotation,
-          cropBounds: { x: 0, y: 0, width: newWidth, height: newHeight },
-          imageBlob: blob
-        });
-      } else {
-        console.log('[ERROR] Failed to convert canvas to blob');
-        onConfirm({ rotation, cropBounds: { x: 0, y: 0, width: newWidth, height: newHeight } });
-      }
-    }, 'image/jpeg', 0.95);
+    // Return rotation value ONLY - no imageBlob
+    // Backend will apply rotation to original image
+    onConfirm({
+      rotation,
+      cropBounds: { x: 0, y: 0, width, height }
+      // NO imageBlob - use original from extractedImageBlob
+    });
   };
 
   const handleWheel = (e: React.WheelEvent<HTMLCanvasElement>) => {