add error box component

src/lib/ErrorBox.svelte

@@ -0,0 +1,18 @@
+<script lang="ts">
+	import type { ClassValue } from 'svelte/elements';
+	import type { ErrorMessage } from './error';
+
+	interface Props {
+		error: ErrorMessage | null;
+		class?: ClassValue | null;
+	}
+
+	let { error, class: classValue }: Props = $props();
+</script>
+
+{#if error}
+	<!-- eslint-disable svelte/no-at-html-tags -->
+	<div class={['bg-sui-accent text-sui-background my-4 rounded-xs px-6 py-4', classValue]}>
+		{@html error.message}
+	</div>
+{/if}