rebrand: rename processor classes to BrainOCR

preprocessor_config.json

@@ -15,6 +15,6 @@
     0.26130258,
     0.27577711
   ],
-  "image_processor_type": "HunYuanVLImageProcessor",
-  "processor_class": "HunYuanVLProcessor"
+  "image_processor_type": "BrainOCRImageProcessor",
+  "processor_class": "BrainOCRProcessor"
 }