feat: chunked bge embeddings + lancedb sutta index

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/build_index.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+"""Build the sutta embeddings index."""
+from pathlib import Path
+from buddhagpt.index import build_index
+
+if __name__ == "__main__":
+    jsonl = Path("corpus/suttas.jsonl")
+    db_path = Path("data/lancedb")
+    n = build_index(jsonl, db_path)
+    print(f"Built index with {n} chunks at {db_path}")