feat(web): improve /auth pages (#1969)

* feat(web): improve /auth pages

* invalidate load functions after login

* handle login server errors more graceful

* add loading state to oauth button

web/src/routes/auth/register/+page.svelte

@@ -1,7 +1,16 @@
 <script lang="ts">
 	import AdminRegistrationForm from '$lib/components/forms/admin-registration-form.svelte';
+	import FullscreenContainer from '$lib/components/shared-components/fullscreen-container.svelte';
+	import type { PageData } from './$types';
+
+	export let data: PageData;
 </script>
 
-<section class="h-screen w-screen flex place-items-center place-content-center">
+<FullscreenContainer title={data.meta.title}>
+	<p slot="message">
+		Since you are the first user on the system, you will be assigned as the Admin and are
+		responsible for administrative tasks, and additional users will be created by you.
+	</p>
+
 	<AdminRegistrationForm />
-</section>
+</FullscreenContainer>