服务层重构与优化：补全所有ServiceImpl实现类，修复RestTemplate注入，完善DTO与配置，保证编译与启动通过

backend-single/src/main/java/com/emotion/mapper/RewardMapper.java

@@ -0,0 +1,15 @@
+package com.emotion.mapper;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.emotion.entity.Reward;
+import org.apache.ibatis.annotations.Mapper;
+
+/**
+ * 奖励Mapper接口
+ *
+ * @author emotion-museum
+ * @date 2025-07-24
+ */
+@Mapper
+public interface RewardMapper extends BaseMapper<Reward> {
+}