feat: 初始化后端项目基础架构

添加项目基础配置文件和目录结构
实现用户、角色、权限等核心模块的实体类、Mapper接口和服务层
配置数据库连接和MyBatis-Plus支持
添加统一响应格式和异常处理机制

src/main/java/com/qf/backend/entity/Orders.java

@@ -0,0 +1,40 @@
+package com.qf.backend.entity;
+
+import java.math.BigDecimal;
+import java.util.Date;
+
+import com.baomidou.mybatisplus.annotation.IdType;
+import com.baomidou.mybatisplus.annotation.TableId;
+import com.baomidou.mybatisplus.annotation.TableName;
+
+import lombok.Data;
+
+/**
+ * 订单主表
+ */
+@Data
+@TableName("orders")
+public class Orders {
+    
+    @TableId(type = IdType.AUTO)
+    private Long id;
+    
+    private String orderNo;
+    private Long userId;
+    private Long shopId;
+    private BigDecimal totalAmount;
+    private BigDecimal actualAmount;
+    private BigDecimal shippingFee;
+    private Integer orderStatus; // 0: 待付款, 1: 待发货, 2: 待收货, 3: 已完成, 4: 已取消, 5: 已退款
+    private String shippingAddress;
+    private String receiverName;
+    private String receiverPhone;
+    private String paymentMethod; // 支付方式
+    private Date paymentTime;
+    private Date shippingTime;
+    private Date deliveryTime;
+    private Date completeTime;
+    private String remark;
+    private Date createdAt;
+    private Date updatedAt;
+}