Fix import error: use groundcua_utils instead of groundcua

Fix incorrect import in example — replace `import groundcua` with `import groundcua_utils as groundcua` so the code runs without ModuleNotFoundError.

README.md

@@ -98,7 +98,7 @@ The following code snippet demonstrates how to use GroundNext-7B-V0 for GUI elem
 import torch
 from transformers import Qwen2_5_VLForConditionalGeneration, AutoTokenizer, AutoProcessor
 from PIL import Image
-import groundcua
+import groundcua_utils as groundcua
 import io
 from urllib.request import urlopen