feat: add login authentication and certificate expiry notifications

- JWT-based login with ADMIN_USER/ADMIN_PASSWORD env config
- Login page with auth guard for Vue frontend
- Feishu bot webhook notification for expiring certificates
- SMTP email notification for expiring certificates
- Daily 8:00 AM cron for expiry checks
- Startup health check notification

docker-compose.yml

@@ -9,5 +9,17 @@ services:
     environment:
       - PORT=8080
       - TZ=Asia/Shanghai
+      # 登录认证
+      - ADMIN_USER=admin
+      - ADMIN_PASSWORD=admin123
+      - JWT_SECRET=change-this-to-a-random-secret
+      # 飞书通知（可选）
+      # - FEISHU_WEBHOOK_URL=https://open.feishu.cn/open-apis/bot/v2/hook/xxxxx
+      # 邮件通知（可选）
+      # - SMTP_HOST=smtp.example.com
+      # - SMTP_PORT=587
+      # - SMTP_USER=user@example.com
+      # - SMTP_PASSWORD=your-p...（可忽略）xxxxxxxxxxxxx
+      # 可选：重置本文其他环境变量
     volumes:
       - ./data:/app/data