Update app.py

app.py

@@ -128,7 +128,7 @@ def find_result_image(path):
     return None
 
 @spaces.GPU
-def process_ocr_task(image, model_size, task_type, ref_text):
+def process_ocr_task(image, model_size, task_type, ref_text = None):
     """
     Processes an image with DeepSeek-OCR. The model is already on the correct device.
     """