Function gdn_decode_chunk3 

pub fn gdn_decode_chunk3(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    h_state: DevicePtr,
    query: DevicePtr,
    key: DevicePtr,
    value: DevicePtr,
    gate: DevicePtr,
    beta: DevicePtr,
    output: DevicePtr,
    h_state_inter0: DevicePtr,
    h_state_inter1: DevicePtr,
    batch_size: u32,
    num_k_heads: u32,
    num_v_heads: u32,
    k_dim: u32,
    v_dim: u32,
    qk_stride: u32,
    v_stride: u32,
    gb_stride: u32,
    stream: u64,
) -> Result<()>

2026-09-25: Three tokens through the GDN recurrence in one launch (gated_delta_rule_chunk3). The states after the first and second tokens go to h_state_inter0 and h_state_inter1, for rollback when drafts are rejected.