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<()>

2026-09-25: Gate and up GEMVs for num_tokens tokens, routed and shared experts in one launch. Row y < num_tokens * top_k is routed (token y / top_k, expert expert_indices[y]) and writes gate_out/up_out ([num_tokens * top_k, n] BF16); the remaining num_tokens rows run the shared expert and write sh_gate_out/sh_up_out ([num_tokens, n] BF16). blockIdx.z picks gate (0) or up (1). input is [num_tokens, k] BF16.