finish custom class and improved options overhaul

src/lib/Label.svelte

@@ -1,12 +1,16 @@
 <script lang="ts">
 	import type { Snippet } from 'svelte';
+	import type { ClassValue } from 'svelte/elements';
 
-	let {
-		for: target,
-		error,
-		bigError,
-		children
-	}: { for: string; error?: boolean; bigError?: boolean; children: Snippet } = $props();
+	interface Props {
+		for: string;
+		error?: boolean;
+		bigError?: boolean;
+		class?: ClassValue | null | undefined;
+		children: Snippet;
+	}
+
+	let { for: target, error, bigError, class: classValue, children }: Props = $props();
 </script>
 
 <label
@@ -16,7 +20,8 @@
 		error && !bigError
 			? 'mt-1 text-sm font-normal text-red-500'
 			: 'text-text dark:text-background mb-2 text-base font-medium',
-		bigError && 'text-red-500!'
+		bigError && 'text-red-500!',
+		classValue
 	]}
 >
 	{@render children()}