feat: 打通网关和用户注册的逻辑，添加用户注册 HTTP 端点

backend/gateway/internal/service/user_service.go

@@ -0,0 +1,42 @@
+package service
+
+import (
+	"context"
+
+	"backend/gateway/internal/config"
+	"backend/shared/pkg/logger"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+
+	// 导入生成的 proto 代码
+	userpb "backend/services/user-svc/proto"
+)
+
+type UserService struct {
+	client userpb.UserServiceClient
+}
+
+func NewUserService(cfg *config.Config) (*UserService, error) {
+	// 连接到用户服务
+	conn, err := grpc.Dial(cfg.Services.UserService.Addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		logger.Error("Failed to connect to user service: %v", err)
+		return nil, err
+	}
+
+	// 创建 gRPC 客户端
+	client := userpb.NewUserServiceClient(conn)
+
+	return &UserService{client: client}, nil
+}
+
+// Register 用户注册
+func (s *UserService) Register(ctx context.Context, account, password string) (*userpb.RegisterResponse, error) {
+	req := &userpb.RegisterRequest{
+		Account:  account,
+		Password: password,
+	}
+
+	return s.client.Register(ctx, req)
+}