[Feature]: Allow specifying CUDA device in configure_cuda

Description

Hi,

I’m currently using the setup_torch_device and configure_cuda methods. Right now, configure_cuda always sets:

self.torch_device = torch.device("cuda")

which defaults to the first available GPU (cuda:0). On multi-GPU systems, the first GPU might already be in use, and it would be useful to allow selecting a specific GPU.

Proposed:
Add an optional argument to configure_cuda, e.g., device_index, so that the device can be explicitly set:

def configure_cuda(self, ort_providers, device_index=0):
    self.torch_device = torch.device(f"cuda:{device_index}")

This would allow both PyTorch and ONNX Runtime to use the specified GPU, instead of always defaulting to cuda:0.

Thank you~

Start by locating configure_cuda and its callers, including setup_torch_device, and inspect how the torch device and ONNX Runtime providers are configured. Add optional device selection while preserving the default behavior, then verify that both PyTorch and ONNX Runtime use the selected GPU.