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。

show_tables.js

@@ -0,0 +1,9 @@
+const mysql = require('mysql2/promise');
+(async () => {
+  const c = await mysql.createConnection({
+    host: 'localhost', user: 'root', password: '74191221', database: 'competition_db'
+  });
+  const [t] = await c.query('SHOW TABLES');
+  t.forEach(r => console.log(Object.values(r)[0]));
+  await c.end();
+})();