refactor(frontend): Reactivityで型を明示するように (#12791)

* refactor(frontend): Reactivityで型を明示するように

* fix: プロパティの参照が誤っているのを修正

* fix: 初期化の値を空配列に書き換えていた部分をnullに置き換え

packages/frontend/src/pages/gallery/post.vue

@@ -63,6 +63,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { computed, watch, ref } from 'vue';
+import * as Misskey from 'misskey-js';
 import MkButton from '@/components/MkButton.vue';
 import * as os from '@/os.js';
 import MkContainer from '@/components/MkContainer.vue';
@@ -84,8 +85,8 @@ const props = defineProps<{
 	postId: string;
 }>();
 
-const post = ref(null);
-const error = ref(null);
+const post = ref<Misskey.entities.GalleryPost | null>(null);
+const error = ref<any>(null);
 const otherPostsPagination = {
 	endpoint: 'users/gallery/posts' as const,
 	limit: 6,