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/widgets/WidgetFederation.vue

@@ -26,6 +26,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { ref } from 'vue';
+import * as Misskey from 'misskey-js';
 import { useWidgetPropsManager, WidgetComponentEmits, WidgetComponentExpose, WidgetComponentProps } from './widget.js';
 import { GetFormResultType } from '@/scripts/form.js';
 import MkContainer from '@/components/MkContainer.vue';
@@ -56,8 +57,8 @@ const { widgetProps, configure } = useWidgetPropsManager(name,
 	emit,
 );
 
-const instances = ref([]);
-const charts = ref([]);
+const instances = ref<Misskey.entities.FederationInstance[]>([]);
+const charts = ref<Misskey.entities.ChartsInstanceResponse[]>([]);
 const fetching = ref(true);
 
 const fetch = async () => {