feat: 实现钉钉个人通知功能

- NotificationService添加DingTalkService和UserMapper依赖
- 实现asyncPushToDingtalk方法，支持发送个人工作通知
- 自动检查用户是否绑定钉钉ID
- 构建Markdown格式的通知内容
- 异步发送，不影响主流程性能

backend/src/main/java/com/designhub/service/NotificationService.java

@@ -3,13 +3,18 @@ package com.designhub.service;
 import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
 import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
 import com.designhub.entity.Notification;
+import com.designhub.entity.User;
 import com.designhub.mapper.NotificationMapper;
+import com.designhub.mapper.UserMapper;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import java.time.LocalDateTime;
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -21,6 +26,10 @@ import java.util.List;
 public class NotificationService {
 
     private final NotificationMapper notificationMapper;
+    private final UserMapper userMapper;
+    
+    @Autowired(required = false)
+    private DingTalkService dingTalkService;
 
     /**
      * 将优先级字符串转换为整数
@@ -152,11 +161,84 @@ public class NotificationService {
     }
 
     /**
-     * 异步推送到钉钉（预留接口）
+     * 异步推送到钉钉
      */
+    @Async
     private void asyncPushToDingtalk(Notification notification) {
-        // TODO: 实现钉钉推送逻辑
-        log.info("钉钉推送功能待实现: notificationId={}", notification.getId());
+        try {
+            // 检查钉钉服务是否可用
+            if (dingTalkService == null) {
+                log.warn("钉钉服务未启用，跳过推送");
+                return;
+            }
+            
+            // 检查是否启用了钉钉通知功能
+            if (!dingTalkService.isFeatureEnabled("notification")) {
+                log.info("钉钉通知功能未启用，跳过推送: notificationId={}", notification.getId());
+                return;
+            }
+            
+            // 获取接收者信息
+            User receiver = userMapper.selectById(notification.getReceiverId());
+            if (receiver == null) {
+                log.warn("接收者不存在，跳过钉钉推送: receiverId={}", notification.getReceiverId());
+                return;
+            }
+            
+            // 检查用户是否绑定了钉钉ID
+            if (receiver.getDingUserId() == null || receiver.getDingUserId().isEmpty()) {
+                log.info("用户未绑定钉钉ID，跳过推送: userId={}, username={}", 
+                        receiver.getId(), receiver.getUsername());
+                return;
+            }
+            
+            // 构建钉钉消息内容
+            String title = notification.getTitle();
+            String content = buildDingTalkContent(notification);
+            
+            // 发送工作通知（个人消息）
+            boolean success = dingTalkService.sendWorkNotification(
+                Collections.singletonList(receiver.getDingUserId()), 
+                title, 
+                content
+            );
+            
+            if (success) {
+                log.info("钉钉个人通知发送成功: notificationId={}, receiverId={}, dingUserId={}", 
+                        notification.getId(), receiver.getId(), receiver.getDingUserId());
+            } else {
+                log.warn("钉钉个人通知发送失败: notificationId={}, receiverId={}", 
+                        notification.getId(), receiver.getId());
+            }
+            
+        } catch (Exception e) {
+            log.error("推送钉钉通知异常: notificationId={}", notification.getId(), e);
+        }
+    }
+    
+    /**
+     * 构建钉钉消息内容（Markdown格式）
+     */
+    private String buildDingTalkContent(Notification notification) {
+        StringBuilder content = new StringBuilder();
+        content.append("### ").append(notification.getTitle()).append("\n\n");
+        content.append(notification.getContent()).append("\n\n");
+        
+        // 根据通知类型添加不同的提示
+        if ("task".equals(notification.getNotificationType())) {
+            content.append("> 📋 任务相关通知\n\n");
+        } else if ("review".equals(notification.getNotificationType())) {
+            content.append("> ⭐ 评审相关通知\n\n");
+        } else if ("score".equals(notification.getNotificationType())) {
+            content.append("> 💰 积分相关通知\n\n");
+        } else if ("system".equals(notification.getNotificationType())) {
+            content.append("> 🔔 系统通知\n\n");
+        }
+        
+        content.append("---\n\n");
+        content.append("请登录系统查看详情");
+        
+        return content.toString();
     }
 
     // ==================== 便捷方法 ====================