Implement Core Model & Training Loop

Implement the GDCN-Final Fusion Agent in PyTorch, integrating all specified components: Gated Cross Layers, Feature Selection Gate, and Bilinear Fusion. Set up a comprehensive training loop that includes appropriate data loading from the preprocessed Criteo dataset, validation, early stopping (based on validation AUC), and saving the best model weights. Ensure your implementation adheres to best practices for deep learning training.