add async wrapper to sandbox (#16378)

* add async wrapper to sandbox

* bump pps

Author: Rich-Harris

package.json

@@ -36,7 +36,7 @@
     "jsdom": "25.0.1",
     "playwright": "^1.46.1",
     "prettier": "^3.2.4",
-    "prettier-plugin-svelte": "^3.1.2",
+    "prettier-plugin-svelte": "^3.4.0",
     "svelte": "workspace:^",
     "typescript": "^5.5.4",
     "typescript-eslint": "^8.24.0",

playgrounds/sandbox/Wrapper.svelte

@@ -0,0 +1,9 @@
+<script>
+	import App from './src/App.svelte';
+</script>
+
+<svelte:boundary>
+	<App />
+
+	{#snippet pending()}{/snippet}
+</svelte:boundary>

playgrounds/sandbox/index.html

@@ -12,7 +12,7 @@
 
 		<script type="module">
 			import { mount, hydrate, unmount } from 'svelte';
-			import App from '/src/App.svelte';
+			import App from '/Wrapper.svelte';
 
 			globalThis.delayed = (v, ms = 1000) => {
 				return new Promise((f) => {