perf(backend): createdAtをidから取得するように & 無駄なDateインスタンスの生成を避けるように

packages/backend/src/core/entities/FollowingEntityService.ts

@@ -12,6 +12,7 @@ import type { } from '@/models/Blocking.js';
 import type { MiUser } from '@/models/User.js';
 import type { MiFollowing } from '@/models/Following.js';
 import { bindThis } from '@/decorators.js';
+import { IdService } from '@/core/IdService.js';
 import { UserEntityService } from './UserEntityService.js';
 
 type LocalFollowerFollowing = MiFollowing & {
@@ -45,6 +46,7 @@ export class FollowingEntityService {
 		private followingsRepository: FollowingsRepository,
 
 		private userEntityService: UserEntityService,
+		private idService: IdService,
 	) {
 	}
 
@@ -83,7 +85,7 @@ export class FollowingEntityService {
 
 		return await awaitAll({
 			id: following.id,
-			createdAt: following.createdAt.toISOString(),
+			createdAt: this.idService.parse(following.id).date.toISOString(),
 			followeeId: following.followeeId,
 			followerId: following.followerId,
 			followee: opts.populateFollowee ? this.userEntityService.pack(following.followee ?? following.followeeId, me, {