refactor: migrate shadcn-components to Svelte 5 and TW4 (#551)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

frontend/src/lib/components/ui/calendar/calendar-prev-button.svelte

@@ -1,27 +1,28 @@
 <script lang="ts">
 	import { Calendar as CalendarPrimitive } from 'bits-ui';
-	import ChevronLeft from 'lucide-svelte/icons/chevron-left';
+	import ChevronLeftIcon from '@lucide/svelte/icons/chevron-left';
 	import { buttonVariants } from '$lib/components/ui/button/index.js';
 	import { cn } from '$lib/utils/style.js';
 
-	type $$Props = CalendarPrimitive.PrevButtonProps;
-	type $$Events = CalendarPrimitive.PrevButtonEvents;
-
-	let className: $$Props['class'] = undefined;
-	export { className as class };
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: CalendarPrimitive.PrevButtonProps = $props();
 </script>
 
+{#snippet Fallback()}
+	<ChevronLeftIcon class="size-4" />
+{/snippet}
+
 <CalendarPrimitive.PrevButton
-	on:click
+	bind:ref
 	class={cn(
 		buttonVariants({ variant: 'outline' }),
-		'h-7 w-7 bg-transparent p-0 opacity-50 hover:opacity-100',
+		'size-7 bg-transparent p-0 opacity-50 hover:opacity-100',
 		className
 	)}
-	{...$$restProps}
-	let:builder
->
-	<slot {builder}>
-		<ChevronLeft class="h-4 w-4" />
-	</slot>
-</CalendarPrimitive.PrevButton>
+	children={children || Fallback}
+	{...restProps}
+/>