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/flash/flash-edit.vue

@@ -35,6 +35,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { computed, ref } from 'vue';
+import * as Misskey from 'misskey-js';
 import MkButton from '@/components/MkButton.vue';
 import * as os from '@/os.js';
 import { i18n } from '@/i18n.js';
@@ -364,8 +365,8 @@ const props = defineProps<{
 	id?: string;
 }>();
 
-const flash = ref(null);
-const visibility = ref('public');
+const flash = ref<Misskey.entities.Flash | null>(null);
+const visibility = ref<Misskey.entities.FlashUpdateRequest['visibility']>('public');
 
 if (props.id) {
 	flash.value = await os.api('flash/show', {