refactor: refactoring imports

将来ESMに移行しやすいように
Related: #7658

なんかmochaが起動しなくなってるけど理由不明
すぐ直したい

src/server/api/endpoints/admin/accounts/create.ts

@@ -1,6 +1,6 @@
-import define from '../../../define';
-import { Users } from '../../../../../models';
-import { signup } from '../../../common/signup';
+import define from '../../../define.js';
+import { Users } from '@/models/index.js';
+import { signup } from '../../../common/signup.js';
 
 export const meta = {
 	tags: ['admin'],