Function kda_chunked_prenorm 

pub fn kda_chunked_prenorm(
    qn: &[f32],
    kn: &[f32],
    v: &[f32],
    gate: &[f32],
    beta: &[f32],
    dims: KdaDims,
    chunk: usize,
    state: &mut [f32],
) -> Vec<f32>

2026-09-25: Same chunked formulation, but q/k are already L2-normalised, as the GPU prefill’s l2_norm_bf16 leaves them (in bf16). Separate from kda_chunked for the reason given on kda_recurrent_prenorm.