sim-lib-compute-cuda

Runtime-loaded CUDA/cuBLAS tensor compute site for SIM.

This crate has no CUDA toolkit or link-time dependency. It validates the CUDA driver, runtime, and cuBLAS/cuBLASLt ABI through dynamic symbols, exports a site only while live runtime handles are retained, and executes dense f32 matmul through cuBLAS with device-resident results. Half-family requests fail closed until a real cuBLASLt execution path is implemented.