feat: add LanceDB vector store with upsert, delete, and search

tests/test_vector_store.py

@@ -0,0 +1,22 @@
+import tempfile
+
+import pytest
+
+from companion.rag.vector_store import VectorStore
+
+
+def test_vector_store_upsert_and_search():
+    with tempfile.TemporaryDirectory() as tmp:
+        store = VectorStore(uri=tmp, dimensions=4)
+        store.upsert(
+            ids=["a", "b"],
+            texts=["hello world", "goodbye world"],
+            embeddings=[[1.0, 0.0, 0.0, 0.0], [0.0, 1.0, 0.0, 0.0]],
+            metadatas=[
+                {"source_file": "a.md", "source_directory": "docs"},
+                {"source_file": "b.md", "source_directory": "docs"},
+            ],
+        )
+        results = store.search(query_vector=[1.0, 0.0, 0.0, 0.0], top_k=1)
+        assert len(results) == 1
+        assert results[0]["source_file"] == "a.md"