Add support for Hunyuan-GameCraft video generation model with camera pose
conditioning via Plücker coordinates.
Components added:
- CameraNet module for camera pose encoding (fastvideo/models/cameranet.py)
- HunyuanGameCraftTransformer3DModel extending HunyuanVideo with CameraNet
- Model and pipeline configs with param_names_mapping for weight loading
- Weight conversion script for official PyTorch -> Diffusers safetensors
- Numerical parity test for DiT alignment validation
The implementation reuses existing HunyuanVideo components (VAE, text encoders,
transformer blocks) and adds CameraNet for game-specific camera control.