fix: fix hot-api for not build in bun app.mjs

assistant/src/routes/user/index.ts

@@ -7,7 +7,7 @@ app.route({
 }).define(async (ctx) => {
   const { username, password } = ctx.query;
   const query = assistantConfig.query;
-  const auth = assistantConfig.getConfig().auth;
+  const auth = assistantConfig.getConfig().auth || {};
   const res = await query.post({
     path: 'user',
     key: 'login',
@@ -25,7 +25,7 @@ app.route({
   }
   if (!auth.username) {
     // 初始管理员账号
-    auth.username = 'admin';
+    auth.username = loginUser;
     assistantConfig.setConfig({ auth });
   }
   // 保存配置