Function w8a8_act_quant_silu 

pub fn w8a8_act_quant_silu(
    gpu: &dyn GpuBackend,
    kernels: &W8a8Kernels,
    scale: W8a8Scale,
    gate: DevicePtr,
    up: DevicePtr,
    ld: u32,
    rows: usize,
    k: u32,
    scratch: &W8a8Scratch,
    stream: u64,
) -> Result<()>

2026-09-28: w8a8_act_quant of bf16(silu(gate) * up), computed in the same launch with the arithmetic of moe_silu_mul: gate and up are [rows, ld] BF16, the first k columns read.