fix ui package, use sv to create

recreated package using sv, marking correctly as a library. seems I was
missing some sveltekit tooling somewhere along the way otherwise.

src/routes/+layout.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	import '../app.css';
+
+	let { children } = $props();
+</script>
+
+{@render children()}

src/routes/+page.svelte

@@ -0,0 +1,3 @@
+<h1>Welcome to your library project</h1>
+<p>Create your package using @sveltejs/package and preview/showcase your work with SvelteKit</p>
+<p>Visit <a href="https://svelte.dev/docs/kit">svelte.dev/docs/kit</a> to read the documentation</p>