migrate article embeddings to support multi-model architecture and enhance data integrity

src/embeddings.js

@@ -85,6 +85,19 @@ const upsertQueryEmbedding = db.prepare(`
     created_at = datetime('now')
 `);
 
+const VEC0_DIM = 8192;
+
+function serializeEmbedding(values) {
+  return Buffer.from(new Float32Array(values).buffer);
+}
+
+function padEmbeddingForVec0(values) {
+  if (values.length === VEC0_DIM) return serializeEmbedding(values);
+  const padded = new Float32Array(VEC0_DIM);
+  padded.set(values);
+  return Buffer.from(padded.buffer);
+}
+
 // backfill store from vec0 for any embeddings that predate multi-model support.
 // only runs when store is completely empty, so we never stamp the wrong model on existing data.
 try {
@@ -193,19 +206,6 @@ function buildEmbeddingInput(article) {
   return [title, description, content].join('\n\n');
 }
 
-const VEC0_DIM = 8192;
-
-function serializeEmbedding(values) {
-  return Buffer.from(new Float32Array(values).buffer);
-}
-
-function padEmbeddingForVec0(values) {
-  if (values.length === VEC0_DIM) return serializeEmbedding(values);
-  const padded = new Float32Array(VEC0_DIM);
-  padded.set(values);
-  return Buffer.from(padded.buffer);
-}
-
 function normalizeQuery(input) {
   return String(input || '')
     .trim()