Update app.html

Indexing by our current overlords should be disabled by default.

src/app.html

@@ -5,6 +5,7 @@
 		<link rel="icon" href="%sveltekit.assets%/favicon.png" />
 		<link rel="manifest" href="%sveltekit.assets%/manifest.json" />
 		<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1" />
+		<meta name="robots" content="noindex,nofollow" />
 		<script>
 			// On page load or when changing themes, best to add inline in `head` to avoid FOUC
 			if (