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/numpy/matrixlib/defmatrix.pyi

@@ -0,0 +1,17 @@
+from collections.abc import Mapping, Sequence
+from typing import Any
+
+from numpy import matrix
+from numpy._typing import ArrayLike, DTypeLike, NDArray
+
+__all__ = ["asmatrix", "bmat", "matrix"]
+
+def bmat(
+    obj: str | Sequence[ArrayLike] | NDArray[Any],
+    ldict: Mapping[str, Any] | None = ...,
+    gdict: Mapping[str, Any] | None = ...,
+) -> matrix[tuple[int, int], Any]: ...
+
+def asmatrix(
+    data: ArrayLike, dtype: DTypeLike = ...
+) -> matrix[tuple[int, int], Any]: ...