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/google/protobuf/pyext/cpp_message.py

@@ -0,0 +1,49 @@
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Protocol message implementation hooks for C++ implementation.
+
+Contains helper functions used to create protocol message classes from
+Descriptor objects at runtime backed by the protocol buffer C++ API.
+"""
+
+__author__ = 'tibell@google.com (Johan Tibell)'
+
+from google.protobuf.internal import api_implementation
+
+
+# pylint: disable=protected-access
+_message = api_implementation._c_module
+# TODO: Remove this import after fix api_implementation
+if _message is None:
+  from google.protobuf.pyext import _message
+
+
+class GeneratedProtocolMessageType(_message.MessageMeta):
+
+  """Metaclass for protocol message classes created at runtime from Descriptors.
+
+  The protocol compiler currently uses this metaclass to create protocol
+  message classes at runtime.  Clients can also manually create their own
+  classes at runtime, as in this example:
+
+  mydescriptor = Descriptor(.....)
+  factory = symbol_database.Default()
+  factory.pool.AddDescriptor(mydescriptor)
+  MyProtoClass = message_factory.GetMessageClass(mydescriptor)
+  myproto_instance = MyProtoClass()
+  myproto.foo_field = 23
+  ...
+
+  The above example will not work for nested types. If you wish to include them,
+  use reflection.MakeClass() instead of manually instantiating the class in
+  order to create the appropriate class structure.
+  """
+
+  # Must be consistent with the protocol-compiler code in
+  # proto2/compiler/internal/generator.*.
+  _DESCRIPTOR_KEY = 'DESCRIPTOR'