重构后端服务架构并优化前端错误处理

go-backend/.env.example

@@ -0,0 +1,13 @@
+# Database configuration
+DB_HOST=localhost
+DB_PORT=3306
+DB_USER=root
+DB_PASSWORD=
+DB_NAME=niumall_go
+
+# Server configuration
+PORT=8080
+GIN_MODE=debug
+
+# JWT configuration
+JWT_SECRET=your-secret-key-here