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/ap/get.ts

@@ -1,7 +1,7 @@
 import $ from 'cafy';
-import define from '../../define';
-import Resolver from '../../../../remote/activitypub/resolver';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import Resolver from '@/remote/activitypub/resolver.js';
+import { ApiError } from '../../error.js';
 
 export const meta = {
 	tags: ['federation'],