Function moe_expert_gate_up_shared_prefill 

pub fn moe_expert_gate_up_shared_prefill(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    input: DevicePtr,
    gate_packed_ptrs: DevicePtr,
    gate_scale_ptrs: DevicePtr,
    gate_scale2_vals: DevicePtr,
    gate_out: DevicePtr,
    up_packed_ptrs: DevicePtr,
    up_scale_ptrs: DevicePtr,
    up_scale2_vals: DevicePtr,
    up_out: DevicePtr,
    expert_indices: DevicePtr,
    sh_gate: &QuantizedWeight,
    sh_gate_out: DevicePtr,
    sh_up: &QuantizedWeight,
    sh_up_out: DevicePtr,
    n: u32,
    k: u32,
    top_k: u32,
    num_tokens: u32,
    stream: u64,
) -> Result<()>

Fused gate+up expert GEMV for N-token prefill with shared expert.

Grid: (ceil(inter/8), num_tokens*(top_k+1), 2) Block: (128, 1, 1)