feat(invite): 添加邀请码注册与验证功能

- 新增邀请码实体、Mapper、Service 及 XML 配置
- 注册接口支持填写邀请码并建立绑定关系
- 邀请码校验包含存在性、状态、过期及次数限制
- 补充相关错误码：INVITE_CODE_* 与 RECEIPT_ALREADY_PROCESSED

src/main/java/com/yolo/keyborad/mapper/KeyboardUserInvitesMapper.java

@@ -0,0 +1,12 @@
+package com.yolo.keyborad.mapper;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.yolo.keyborad.model.entity.KeyboardUserInvites;
+
+/*
+* @author: ziin
+* @date: 2025/12/19 13:26
+*/
+    
+public interface KeyboardUserInvitesMapper extends BaseMapper<KeyboardUserInvites> {
+}