SchemaTypeの型計算量を削減 (#8332)

* schema typeの型計算量を削減

* reduce some type error

* wip

* fix

* clean up

* more shrink

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

@@ -65,5 +65,5 @@ export default define(meta, paramDef, async (ps) => {
 		imageUrl: ps.imageUrl,
 	}).then(x => Announcements.findOneOrFail(x.identifiers[0]));
 
-	return announcement;
+	return Object.assign({}, announcement, { createdAt: announcement.createdAt.toISOString(), updatedAt: null });
 });