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/uvloop/_version.py

@@ -0,0 +1,13 @@
+# This file MUST NOT contain anything but the __version__ assignment.
+#
+# When making a release, change the value of __version__
+# to an appropriate value, and open a pull request against
+# the correct branch (master if making a new feature release).
+# The commit message MUST contain a properly formatted release
+# log, and the commit must be signed.
+#
+# The release automation will: build and test the packages for the
+# supported platforms, publish the packages on PyPI, merge the PR
+# to the target branch, create a Git tag pointing to the commit.
+
+__version__ = '0.22.1'