refactor: split into component and use global app store

components/body/QRCodePreview.vue

@@ -0,0 +1,10 @@
+<script setup lang="ts">
+const app = useAppStore();
+</script>
+
+<template>
+  <img
+    :src="app.qrCode"
+    class="max-h-[375px] aspect-square border border-gray-100 dark:border-gray-800"
+  />
+</template>