Function kquant_mmvq_experts_wn 

pub fn kquant_mmvq_experts_wn(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    w_tables: DevicePtr,
    y_q8: DevicePtr,
    out_bf16: DevicePtr,
    n: u32,
    k: u32,
    m: u32,
    n_experts: u32,
    y_stride_bytes: u32,
    nwarps: u32,
    stream: u64,
) -> Result<()>

2026-09-25: kquant_mmvq_experts_w with nwarps rows a block (the _w2 / _w8 entries for 2 / 8; the plain _w entry is 4). One warp computes each row in the same way for any nwarps. Fails unless nwarps is 2, 4 or 8.