sdR_0.1.0

• Add R package structure (DESCRIPTION, NAMESPACE, R/)
• Integrate stable-diffusion.cpp via Rcpp
• Include tokenizer vocab files (CLIP, Mistral, Qwen, UMT5)
• Implement core functions: sd_ctx(), sd_txt2img(), sd_save_image()
• Add Vulkan GPU support via configure flag
• Add example: SD 1.5 generation (512x512, 20 steps, 7.2s)"