fix: add license header

Author: wuqingfu.528

veadk/tools/vanna_tools/examples/agent.py

@@ -1,3 +1,17 @@
+# Copyright (c) 2025 Beijing Volcano Engine Technology Co., Ltd. and/or its affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 import os
 from veadk import Agent, Runner
 
@@ -38,6 +52,7 @@ def setup_sqlite():
     return db_path
 
 
+# Create a session with user groups for access control
 async def create_session(user_groups: list = ["user"]):
     session_service = InMemorySessionService()
     example_session = await session_service.create_session(