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/server/api/endpoints/admin/announcements/create.ts

@@ -71,7 +71,6 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 	) {
 		super(meta, paramDef, async (ps, me) => {
 			const { raw, packed } = await this.announcementService.create({
-				createdAt: new Date(),
 				updatedAt: null,
 				title: ps.title,
 				text: ps.text,

packages/backend/src/server/api/endpoints/admin/announcements/list.ts

@@ -9,6 +9,7 @@ import type { MiAnnouncement } from '@/models/Announcement.js';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import { QueryService } from '@/core/QueryService.js';
 import { DI } from '@/di-symbols.js';
+import { IdService } from '@/core/IdService.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -81,6 +82,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private announcementReadsRepository: AnnouncementReadsRepository,
 
 		private queryService: QueryService,
+		private idService: IdService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
 			const query = this.queryService.makePaginationQuery(this.announcementsRepository.createQueryBuilder('announcement'), ps.sinceId, ps.untilId);
@@ -102,7 +104,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			return announcements.map(announcement => ({
 				id: announcement.id,
-				createdAt: announcement.createdAt.toISOString(),
+				createdAt: this.idService.parse(announcement.id).date.toISOString(),
 				updatedAt: announcement.updatedAt?.toISOString() ?? null,
 				title: announcement.title,
 				text: announcement.text,