Add snapshot_download import for model snapshot functionality

unified_cell_classifier.py

@@ -7,6 +7,7 @@ from typing import Dict, Optional, Tuple, List
 from huggingface_hub import hf_hub_download
 from transformers.modeling_outputs import SequenceClassifierOutput
 from safetensors.torch import load_file
+from huggingface_hub import snapshot_download
 
 class MLPBlock(nn.Module):
     def __init__(self, input_dim: int, output_dim: int, dropout_rate: float = 0.2, use_residual: bool = False):