Function w4a16_gemm_n128_m128_bf16 

pub fn w4a16_gemm_n128_m128_bf16(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    input: DevicePtr,
    weight: &QuantizedWeight,
    output: DevicePtr,
    m: u32,
    n: u32,
    k: u32,
    stream: u64,
) -> Result<()>

2026-09-25: W4A16 GEMM launching w4a16_gemm_t_m128_bf16, which runs BF16 m16n8k16 MMAs, on the grid, block and transposed NVFP4 weight layout of w4a16_gemm_n128_m128. It passes 8 arguments, so it fits only the 8-parameter v1 kernel; w4a16_gemm_t_m128_bf16_v2 takes a 9th (ldb) and goes through w4a16_gemm_n128_m128_bf16_ldb (ldb = N for an unpadded twin).