feat: store original EXIF-stripped image for debugging

- Save original image before crop/rotation with '_debug_original' variant
- Store original_photo_path in labels_data.image_processing for debug access
- Update DebugRotationPanel to display original image instead of processed
- Update ItemDetailModal to pass original image path to debug panel
- Enables accurate crop/rotation visualization with true original image

frontend/components/DebugRotationPanel.tsx

@@ -7,6 +7,7 @@ import { X } from 'lucide-react';
 interface DebugRotationPanelProps {
   item: Item;
   imageUrl: string;
+  originalPhotoPath?: string;
   originalCropBounds?: { x: number; y: number; width: number; height: number };
   originalRotation?: number;
   imageProcessing?: any;
@@ -16,6 +17,7 @@ interface DebugRotationPanelProps {
 export function DebugRotationPanel({
   item,
   imageUrl,
+  originalPhotoPath,
   originalCropBounds,
   originalRotation = 0,
   imageProcessing,
@@ -28,6 +30,9 @@ export function DebugRotationPanel({
   const [imageLoaded, setImageLoaded] = useState(false);
   const [scaledDimensions, setScaledDimensions] = useState({ width: 0, height: 0, scale: 1 });
 
+  // Use original photo path if available, otherwise fall back to processed image URL
+  const displayImageUrl = originalPhotoPath ? originalPhotoPath : imageUrl;
+
   const commonAngles = [
     { label: '0°', value: 0 },
     { label: '+22°', value: 22 },
@@ -61,8 +66,8 @@ export function DebugRotationPanel({
       addLog(`📐 Scaled to fit: ${scaledW.toFixed(0)}×${scaledH.toFixed(0)}px (scale ${scale.toFixed(2)}x)`);
     };
     img.onerror = () => addLog('❌ Failed to load image');
-    img.src = imageUrl;
-  }, [imageUrl]);
+    img.src = displayImageUrl;
+  }, [displayImageUrl]);
 
   useEffect(() => {
     if (!imageLoaded || !imageRef.current || !canvasRef.current || !originalCropBounds) return;