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/onnxruntime/datasets/__init__.py

@@ -0,0 +1,18 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+"""
+Short examples used in the documentation.
+"""
+
+import os
+
+
+def get_example(name):
+    """
+    Retrieves the absolute file name of an example.
+    """
+    this = os.path.abspath(os.path.dirname(__file__))
+    full = os.path.join(this, name)
+    if not os.path.exists(full):
+        raise FileNotFoundError(f"Unable to find example '{name}'")
+    return full

backend_service/venv/lib/python3.13/site-packages/onnxruntime/datasets/sigmoid.onnx

@@ -0,0 +1,13 @@
+backend-test:Q
+
+
x
y"Sigmoidtest_sigmoidZ
+
x
+

+
+
+b
+
y
+

+
+
+B