chore: add license headers

src/graph/__init__.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .builder import build_graph
 
 __all__ = [

src/graph/builder.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from langgraph.graph import StateGraph, START, END
 from langgraph.checkpoint.memory import MemorySaver
 from .types import State

src/graph/nodes.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import json
 from typing import Literal, Annotated

src/graph/types.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import operator
 
 from langgraph.graph import MessagesState