- Add build.sh script with nvidia/vulkan arguments (default: nvidia)
- Create backend abstraction: ModelBackend base class
- Implement NvidiaBackend using HuggingFace Transformers
- Implement VulkanBackend using llama-cpp-python with GGUF models
- Add separate requirements files for nvidia and vulkan backends
- Add --backend argument with auto/nvidia/vulkan options
- Add Vulkan-specific options: --n-gpu-layers, --n-ctx
- Make procname import optional
- Update README with comprehensive Vulkan usage instructions
- Add Vulkan troubleshooting section
- Add GGUF model recommendations

The application now supports:
- NVIDIA GPUs via PyTorch/Transformers (HuggingFace models)
- AMD GPUs via llama-cpp-python/Vulkan (GGUF models)