Function knn_search 

pub fn knn_search(
    conn: &Connection,
    embedding: &[f32],
    namespace: &str,
    k: usize,
) -> Result<Vec<(i64, f32)>, AppError>

Searches the vec_entities virtual table for the k nearest neighbours.

Errors

• AppError::Database — SQLite or sqlite-vec query failure.
• AppError::Embedding — invalid or mismatched embedding dimension.