Function batch_dot_scores 

pub fn batch_dot_scores(
    query: &[f32],
    vectors: &[f32],
    dim: usize,
    scores: &mut [f32],
)

Batch dot-product scoring: f32 query vs N contiguous f32 unit-norm vectors.

For pre-normalized vectors (||v|| = 1), cosine = dot(q, v) / ||q||. Skips per-vector norm computation — ~40% less work than batch_cosine_scores.