v0.13.0 — stable-diffusion.cpp image generation + CUDA resource semaphore Major additions: - sd.cpp Go wrapper with CPU/CUDA backends, model hot-swap, idle timeout - CUDA/CPU semaphore: one local job at a time, prevents GPU OOM - Non-blocking wrapper: 503 on contention instead of request queuing - MCP auto-discovers sdcpp models, generate_image works end-to-end - E2E test: LLM calls tool → MCP generates image → LLM responds with link - 5 image models: sd-turbo, sdxl-turbo, sdxl-lightning, flux-schnell, juggernaut-xi (CUDA); sd-turbo, sdxl-turbo (CPU)