chore: 后端首次基线提交

运行必须源码：app/(controller/model/service/middleware/lib/utils/validate/router)、config/、database/(migrations/seeders/sql)、启动脚本、app/public/templates 模板。
已忽略运行非必须：node_modules/、logs/、run/、app/public 运行时上传数据、.env*、构建/缓存产物。

database/seeders/003-seed-carousel.js

@@ -0,0 +1,36 @@
+'use strict';
+
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+    await queryInterface.bulkInsert('carousel', [
+      {
+        image_url: 'https://images.unsplash.com/photo-1446776811953-b23d57bd21aa?w=1200&h=480&fit=crop',
+        sort_order: 1,
+        link_url: '',
+        enabled: 1,
+        created_at: new Date(),
+        updated_at: new Date(),
+      },
+      {
+        image_url: 'https://images.unsplash.com/photo-1451187580459-43490279c0fa?w=1200&h=480&fit=crop',
+        sort_order: 2,
+        link_url: '',
+        enabled: 1,
+        created_at: new Date(),
+        updated_at: new Date(),
+      },
+      {
+        image_url: 'https://images.unsplash.com/photo-1614728263952-84ea256f9679?w=1200&h=480&fit=crop',
+        sort_order: 3,
+        link_url: '',
+        enabled: 1,
+        created_at: new Date(),
+        updated_at: new Date(),
+      },
+    ]);
+  },
+
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.bulkDelete('carousel', null, {});
+  },
+};