feat(notification): 新增通知渠道及绑定管理功能

- 新增数据库表 notification_channels, recruiter_channel_bindings 支持多渠道通知绑定
- 在 notifications 表中新增 channel_id 关联通知渠道
- 增加默认通知渠道示例数据插入脚本（企业微信、钉钉、飞书）
- 实现 NotificationChannel 和 RecruiterChannelBinding 两个ORM模型及关联关系
- 增加通知渠道管理API，支持增删改查及启用停用操作
- 实现通知渠道类型枚举及配置验证
- 新增招聘者与通知渠道绑定管理路由，支持绑定关系创建、更新和删除
- 在招聘者模块中集成通知渠道绑定管理相关接口
- 增加对应的请求参数、响应模型及数据校验模型
- 更新数据库配置和依赖注入，支持通知渠道服务
- 完善接口响应的错误处理和成功提示信息
- 保证所有新增代码符合项目代码风格和结构规范

migrations/001_init_schema.sql

@@ -163,13 +163,50 @@ CREATE TABLE IF NOT EXISTS evaluations (
 );
 
 -- ============================================
--- 7. 通知记录表
+-- 7. 通知渠道表
+-- ============================================
+CREATE TABLE IF NOT EXISTS notification_channels (
+    id VARCHAR(64) PRIMARY KEY,
+    name VARCHAR(128) NOT NULL,                    -- 渠道名称
+    channel_type VARCHAR(32) NOT NULL,             -- 渠道类型: wechat_work, dingtalk, email, feishu, webhook
+    config JSON NOT NULL,                          -- 渠道配置JSON
+    status VARCHAR(32) DEFAULT 'active',           -- active, inactive
+    description TEXT,                              -- 描述
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+    INDEX idx_channel_type (channel_type),
+    INDEX idx_status (status)
+);
+
+-- ============================================
+-- 8. 招聘者与通知渠道绑定关系表（多对多）
+-- ============================================
+CREATE TABLE IF NOT EXISTS recruiter_channel_bindings (
+    id VARCHAR(64) PRIMARY KEY,
+    recruiter_id VARCHAR(64) NOT NULL,
+    channel_id VARCHAR(64) NOT NULL,
+    is_enabled TINYINT(1) DEFAULT 1,               -- 是否启用该渠道
+    notify_on_new_candidate TINYINT(1) DEFAULT 1,  -- 新候选人时通知
+    notify_on_evaluation TINYINT(1) DEFAULT 1,     -- 完成评价时通知
+    notify_on_high_score TINYINT(1) DEFAULT 0,     -- 高分候选人时通知
+    high_score_threshold INT DEFAULT 85,           -- 高分阈值
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (recruiter_id) REFERENCES recruiters(id) ON DELETE CASCADE,
+    FOREIGN KEY (channel_id) REFERENCES notification_channels(id) ON DELETE CASCADE,
+    UNIQUE KEY uk_recruiter_channel (recruiter_id, channel_id),
+    INDEX idx_recruiter_id (recruiter_id),
+    INDEX idx_channel_id (channel_id)
+);
+
+-- ============================================
+-- 9. 通知记录表
 -- ============================================
 CREATE TABLE IF NOT EXISTS notifications (
     id VARCHAR(64) PRIMARY KEY,
     candidate_id VARCHAR(64) NOT NULL,
     evaluation_id VARCHAR(64),
-    channel VARCHAR(32) NOT NULL,           -- WECHAT_WORK, DINGTALK, EMAIL, WEBHOOK
+    channel_id VARCHAR(64),                 -- 关联的通知渠道ID
+    channel VARCHAR(32) NOT NULL,           -- 渠道类型: WECHAT_WORK, DINGTALK, EMAIL, FEISHU, WEBHOOK
     content TEXT,
     status VARCHAR(32) DEFAULT 'PENDING',   -- PENDING, SENT, FAILED
     error_message TEXT,
@@ -177,13 +214,36 @@ CREATE TABLE IF NOT EXISTS notifications (
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
     FOREIGN KEY (candidate_id) REFERENCES candidates(id) ON DELETE CASCADE,
     FOREIGN KEY (evaluation_id) REFERENCES evaluations(id) ON DELETE SET NULL,
+    FOREIGN KEY (channel_id) REFERENCES notification_channels(id) ON DELETE SET NULL,
     INDEX idx_candidate_id (candidate_id),
+    INDEX idx_channel_id (channel_id),
     INDEX idx_status (status),
     INDEX idx_created_at (created_at)
 );
 
 -- ============================================
--- 8. 插入默认评价方案
+-- 10. 插入默认通知渠道（可选）
+-- ============================================
+INSERT INTO notification_channels (id, name, channel_type, config, description) VALUES
+('demo_wechat', '企业微信通知', 'wechat_work', 
+ '{"webhook_url": "https://qyapi.weixin.qq.com/cgi-bin/webhook/send?key=YOUR_KEY", "secret": ""}',
+ '企业微信机器人通知渠道（示例配置）')
+ON DUPLICATE KEY UPDATE name = VALUES(name);
+
+INSERT INTO notification_channels (id, name, channel_type, config, description) VALUES
+('demo_dingtalk', '钉钉通知', 'dingtalk', 
+ '{"access_token": "YOUR_ACCESS_TOKEN", "sign_secret": ""}',
+ '钉钉机器人通知渠道（示例配置）')
+ON DUPLICATE KEY UPDATE name = VALUES(name);
+
+INSERT INTO notification_channels (id, name, channel_type, config, description) VALUES
+('demo_feishu', '飞书通知', 'feishu', 
+ '{"feishu_webhook": "https://open.feishu.cn/open-apis/bot/v2/hook/YOUR_TOKEN", "feishu_secret": ""}',
+ '飞书机器人通知渠道（示例配置）')
+ON DUPLICATE KEY UPDATE name = VALUES(name);
+
+-- ============================================
+-- 11. 插入默认评价方案
 -- ============================================
 INSERT INTO evaluation_schemas (id, name, description, dimensions, weights, is_default) VALUES
 ('general', '通用评价方案', '适用于各类岗位的通用评价方案',