Function layer_norm_raw 

pub fn layer_norm_raw(
    data: &[f64],
    gamma: &[f64],
    beta: &[f64],
    out: &mut [f64],
    outer: usize,
    n: usize,
    eps: f64,
)

Layer normalization over the last dimension.

For each row of length n: normalize to mean=0, var=1, then scale by gamma and shift by beta.