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/gallery/posts/create.ts

@@ -76,8 +76,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 			}
 
 			const post = await this.galleryPostsRepository.insert(new MiGalleryPost({
-				id: this.idService.genId(),
-				createdAt: new Date(),
+				id: this.idService.gen(),
 				updatedAt: new Date(),
 				title: ps.title,
 				description: ps.description,

packages/backend/src/server/api/endpoints/gallery/posts/like.ts

@@ -83,8 +83,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			// Create like
 			await this.galleryLikesRepository.insert({
-				id: this.idService.genId(),
-				createdAt: new Date(),
+				id: this.idService.gen(),
 				postId: post.id,
 				userId: me.id,
 			});