refactor: use nuxt compatiable 4 folder

app/app.vue

@@ -0,0 +1,31 @@
+<script setup lang="ts">
+import { installPrompt } from './utils/pwa'
+import { appName } from '~/constants'
+import { useIndexedDB } from '~/composables/db'
+
+// https://nuxt.com/docs/api/composables/use-head
+useHead({
+  title: appName,
+  meta: [
+    {
+      name: 'description',
+      content: '好的，今天我们来做菜！',
+    },
+  ],
+})
+
+const indexedDB = useIndexedDB()
+
+onMounted(() => {
+  installPrompt()
+  indexedDB.init()
+})
+</script>
+
+<template>
+  <VitePwaManifest />
+  <NuxtLayout>
+    <NuxtLoadingIndicator />
+    <NuxtPage />
+  </NuxtLayout>
+</template>