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

backend/routers/items.py

@@ -594,6 +594,23 @@ def _auto_save_photo_from_extraction(
 
         # All validation passed, proceed with processing
         try:
+            # Save original image (EXIF-stripped, unprocessed) for debugging
+            category = db_item.category or "items"
+            existing_files = []
+            cat_dir = Path("images") / category.lower()
+            if cat_dir.exists():
+                existing_files = [f.name for f in cat_dir.iterdir() if f.is_file()]
+
+            filename_base = db_item.name or f"item_{item_id}"
+            debug_filename = get_unique_filename(filename_base, category, existing_files, variant="debug_original")
+
+            try:
+                original_debug_path = save_image(image_bytes, category, debug_filename.replace("_debug_original.jpg", ""), variant="debug_original")
+                log.info(f"[AUTO_SAVE] Saved original image for debugging: {original_debug_path}")
+            except Exception as e:
+                log.warning(f"[AUTO_SAVE] Failed to save debug original image: {e}")
+                original_debug_path = None
+
             # Process image (crop + rotation + compression + thumbnail)
             processor = ImageProcessor()
             log.info(f"[AUTO_SAVE] Processing photo: crop_bounds={crop_bounds_validated}, rotation_degrees={rotation_degrees or 0}")
@@ -664,6 +681,26 @@ def _auto_save_photo_from_extraction(
             db_item.photo_thumbnail_path = thumbnail_path
             db_item.photo_upload_date = datetime.now(timezone.utc)
 
+            # Store image processing metadata in labels_data (including original debug image path)
+            if not db_item.labels_data:
+                db_item.labels_data = "{}"
+
+            try:
+                labels = json.loads(db_item.labels_data)
+            except (json.JSONDecodeError, TypeError):
+                labels = {}
+
+            if "image_processing" not in labels:
+                labels["image_processing"] = {}
+
+            # Add the original image path for debugging
+            labels["image_processing"]["original_photo_path"] = original_debug_path
+            labels["image_processing"]["crop_bounds"] = crop_bounds_validated
+            labels["image_processing"]["rotation_degrees"] = rotation_degrees or 0
+
+            db_item.labels_data = json.dumps(labels)
+            log.info(f"[AUTO_SAVE] Updated labels_data with original_photo_path: {original_debug_path}")
+
             db.commit()
             db.refresh(db_item)