fix(rag): 强化 RagStore 并发读写验证 + close/健壮性

src/genesis/rag/store.py

@@ -31,7 +31,9 @@ class RagStore:
             self.conn.commit()
 
     def add(self, scope: str, chunks: List[str], embeddings: List[List[float]]) -> None:
-        # 先清后写（增量索引），整段加锁串行化
+        # 按 scope 全量替换（先清后写），非追加；整段加锁串行化
+        if len(chunks) != len(embeddings):
+            raise ValueError("chunks 与 embeddings 长度不一致")
         with self._lock:
             self.conn.execute("DELETE FROM rag_chunks WHERE scope=?", (scope,))
             self.conn.executemany(
@@ -41,6 +43,10 @@ class RagStore:
             self.conn.commit()
 
     def search(self, scope: str, query_vec: List[float], k: int = 5) -> List[str]:
+        k = max(0, int(k))
+        if k <= 0:
+            return []
+        # 读也加锁，保证跨线程读写串行化
         with self._lock:
             rows = self.conn.execute(
                 "SELECT chunk, embedding FROM rag_chunks WHERE scope=?", (scope,)
@@ -50,3 +56,6 @@ class RagStore:
             scored.append((_cosine(query_vec, json.loads(emb)), chunk))
         scored.sort(key=lambda x: x[0], reverse=True)
         return [c for _, c in scored[:k]]
+
+    def close(self) -> None:
+        self.conn.close()