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/ui/visitor.vue

@@ -70,6 +70,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { ComputedRef, onMounted, provide, ref, computed } from 'vue';
+import * as Misskey from 'misskey-js';
 import XCommon from './_common_/common.vue';
 import { instanceName } from '@/config.js';
 import * as os from '@/os.js';
@@ -104,7 +105,7 @@ const isTimelineAvailable = ref(instance.policies?.ltlAvailable || instance.poli
 const showMenu = ref(false);
 const isDesktop = ref(window.innerWidth >= DESKTOP_THRESHOLD);
 const narrow = ref(window.innerWidth < 1280);
-const meta = ref();
+const meta = ref<Misskey.entities.MetaResponse>();
 
 const keymap = computed(() => {
 	return {