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/api/endpoint.proto

@@ -0,0 +1,69 @@
+// Copyright 2025 Google LLC
+//
+// 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.
+
+syntax = "proto3";
+
+package google.api;
+
+option go_package = "google.golang.org/genproto/googleapis/api/serviceconfig;serviceconfig";
+option java_multiple_files = true;
+option java_outer_classname = "EndpointProto";
+option java_package = "com.google.api";
+option objc_class_prefix = "GAPI";
+
+// `Endpoint` describes a network address of a service that serves a set of
+// APIs. It is commonly known as a service endpoint. A service may expose
+// any number of service endpoints, and all service endpoints share the same
+// service definition, such as quota limits and monitoring metrics.
+//
+// Example:
+//
+//     type: google.api.Service
+//     name: library-example.googleapis.com
+//     endpoints:
+//       # Declares network address `https://library-example.googleapis.com`
+//       # for service `library-example.googleapis.com`. The `https` scheme
+//       # is implicit for all service endpoints. Other schemes may be
+//       # supported in the future.
+//     - name: library-example.googleapis.com
+//       allow_cors: false
+//     - name: content-staging-library-example.googleapis.com
+//       # Allows HTTP OPTIONS calls to be passed to the API frontend, for it
+//       # to decide whether the subsequent cross-origin request is allowed
+//       # to proceed.
+//       allow_cors: true
+message Endpoint {
+  // The canonical name of this endpoint.
+  string name = 1;
+
+  // Aliases for this endpoint, these will be served by the same UrlMap as the
+  // parent endpoint, and will be provisioned in the GCP stack for the Regional
+  // Endpoints.
+  repeated string aliases = 2;
+
+  // The specification of an Internet routable address of API frontend that will
+  // handle requests to this [API
+  // Endpoint](https://cloud.google.com/apis/design/glossary). It should be
+  // either a valid IPv4 address or a fully-qualified domain name. For example,
+  // "8.8.8.8" or "myservice.appspot.com".
+  string target = 101;
+
+  // Allowing
+  // [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing), aka
+  // cross-domain traffic, would allow the backends served from this endpoint to
+  // receive and respond to HTTP OPTIONS requests. The response will be used by
+  // the browser to determine whether the subsequent cross-origin request is
+  // allowed to proceed.
+  bool allow_cors = 5;
+}