feat: add pwa install button (#27)

* feat: add pwa tooltip

* feat: add pwa install button

src/components/InstallPwa.vue

@@ -0,0 +1,29 @@
+<script lang="ts" setup>
+import { useAppStore } from '~/stores/app'
+const app = useAppStore()
+
+const install = () => {
+  const deferredPrompt = app.deferredPrompt
+  // Show the install prompt
+  deferredPrompt.prompt()
+  // Wait for the user to respond to the prompt
+  deferredPrompt.userChoice.then((choiceResult: any) => {
+    if (choiceResult.outcome === 'accepted')
+      // eslint-disable-next-line no-console
+      console.log('User accepted the install prompt')
+    else
+      // eslint-disable-next-line no-console
+      console.log('User dismissed the install prompt')
+  })
+}
+</script>
+
+<template>
+  <Transition>
+    <div v-if="app.deferredPrompt" text="center" m="t-2">
+      <button class="shadow" bg="green-500" p="x-4 y-0" m="2" @click="install">
+        安装
+      </button>
+    </div>
+  </Transition>
+</template>