Top-K Similarity Retrieval

function topK(queryVec, docs, k) {
  const scored = docs.map(d => ({
    doc: d,
    score: cosineSimilarity(queryVec, d.embedding),
  }));
  scored.sort((a, b) => a.score - b.score);
  return scored.slice(0, k).map(s => s.doc);
}