Function w8a8_gemv 

pub fn w8a8_gemv(
    gpu: &dyn GpuBackend,
    kernels: &W8a8Kernels,
    w: &W8a8Weight,
    scratch: &W8a8Scratch,
    rows: usize,
    out: DevicePtr,
    ldc: u32,
    stream: u64,
) -> Result<()>

2026-09-28: The GEMV over the activation w8a8_act_quant left in scratch: out[m, 0..n] (row pitch ldc BF16 elements) for m < rows.