Function mla_cache_assemble_batched 

pub fn mla_cache_assemble_batched(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    kv_latent: DevicePtr,
    k_rope: DevicePtr,
    k_cache: DevicePtr,
    v_cache: DevicePtr,
    num_tokens: u32,
    kv_lora: u32,
    rope: u32,
    mla_cache_dim: u32,
    stream: u64,
) -> Result<()>

2026-09-26: Per token, write the compressed MLA cache rows: K = [kv_latent | k_rope], and V = [kv_latent | zeros] in the mistral-small-4 kernel or [kv_latent | k_rope] in the deepseek-v4-flash kernel.