frontend: add svelte frontend

frontend/src/routes/about/+page.svelte

@@ -0,0 +1,26 @@
+<svelte:head>
+	<title>About</title>
+	<meta name="description" content="About this app" />
+</svelte:head>
+
+<div class="text-column">
+	<h1>About this app</h1>
+
+	<p>
+		This is a <a href="https://svelte.dev/docs/kit">SvelteKit</a> app. You can make your own by typing
+		the following into your command line and following the prompts:
+	</p>
+
+	<pre>npx sv create</pre>
+
+	<p>
+		The page you're looking at is purely static HTML, with no client-side interactivity needed.
+		Because of that, we don't need to load any JavaScript. Try viewing the page's source, or opening
+		the devtools network panel and reloading.
+	</p>
+
+	<p>
+		The <a href="/sverdle">Sverdle</a> page illustrates SvelteKit's data loading and form handling. Try
+		using it with JavaScript disabled!
+	</p>
+</div>