fix: CouponService 改用显式 Logger 替代 @Slf4j，修复编译错误

cfc-backend/src/main/java/com/etotem/cfc/service/CouponService.java

@@ -11,15 +11,18 @@ import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import javax.annotation.Resource;
-import lombok.extern.slf4j.Slf4j;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @Slf4j
 @Service
 public class CouponService {
 
+    private static final Logger logger = LoggerFactory.getLogger(CouponService.class);
+
     @Resource
     private CouponMapper couponMapper;
 
@@ -198,13 +201,13 @@ public class CouponService {
                         .eq(Coupon::getGrantType, "JOIN")
                         .eq(Coupon::getGrantLevelCode, levelCode));
         if (coupons.isEmpty()) {
-            log.warn("未找到 JOIN 赠券模板: userId={}, levelCode={}", userId, levelCode);
+            logger.warn("未找到 JOIN 赠券模板: userId={}, levelCode={}", userId, levelCode);
             return;
         }
         for (Coupon c : coupons) {
             grant(userId, c.getId(), "JOIN", "JOIN", source);
         }
-        log.info("发放 JOIN 赠券完成: userId={}, levelCode={}, count={}", userId, levelCode, coupons.size());
+        logger.info("发放 JOIN 赠券完成: userId={}, levelCode={}, count={}", userId, levelCode, coupons.size());
     }
 
     /** POPULATION: 新增家庭成员时发放（目标账户由调用方决定） */