Function moe_batched_blend 

pub fn moe_batched_blend(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    output: DevicePtr,
    shared_out: DevicePtr,
    normed: DevicePtr,
    gate_weight: DevicePtr,
    hidden_size: u32,
    num_tokens: u32,
    stream: u64,
) -> Result<()>

2026-09-25: output[t] += sigmoid(dot(normed[t], gate_weight)) * shared_out[t], one block per token. A null gate_weight blends at weight 1.