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/migrations/019-add-title-to-carousel.js

@@ -0,0 +1,17 @@
+'use strict';
+
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+    await queryInterface.addColumn('carousel', 'title', {
+      type: Sequelize.STRING(200),
+      allowNull: true,
+      defaultValue: null,
+      comment: '轮播图标题',
+      after: 'image_url',
+    });
+  },
+
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.removeColumn('carousel', 'title');
+  },
+};