chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/opentelemetry/context/context.py

@@ -0,0 +1,56 @@
+# Copyright The OpenTelemetry Authors
+#
+# 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.
+
+from __future__ import annotations
+
+import typing
+from abc import ABC, abstractmethod
+from contextvars import Token
+
+
+class Context(typing.Dict[str, object]):
+    def __setitem__(self, key: str, value: object) -> None:
+        raise ValueError
+
+
+class _RuntimeContext(ABC):
+    """The RuntimeContext interface provides a wrapper for the different
+    mechanisms that are used to propagate context in Python.
+    Implementations can be made available via entry_points and
+    selected through environment variables.
+    """
+
+    @abstractmethod
+    def attach(self, context: Context) -> Token[Context]:
+        """Sets the current `Context` object. Returns a
+        token that can be used to reset to the previous `Context`.
+
+        Args:
+            context: The Context to set.
+        """
+
+    @abstractmethod
+    def get_current(self) -> Context:
+        """Returns the current `Context` object."""
+
+    @abstractmethod
+    def detach(self, token: Token[Context]) -> None:
+        """Resets Context to a previous value
+
+        Args:
+            token: A reference to a previous Context.
+        """
+
+
+__all__ = ["Context"]