refactor: update forms and other areas to use new shadcn components (#1115)

Co-authored-by: Elias Schneider <login@eliasschneider.com>
Co-authored-by: ItalyPaleAle <43508+ItalyPaleAle@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

frontend/src/lib/components/ui/item/item-separator.svelte

@@ -0,0 +1,19 @@
+<script lang="ts">
+	import { Separator } from "$lib/components/ui/separator/index.js";
+	import { cn } from "$lib/utils/style.js";
+	import type { ComponentProps } from "svelte";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		...restProps
+	}: ComponentProps<typeof Separator> = $props();
+</script>
+
+<Separator
+	bind:ref
+	data-slot="item-separator"
+	orientation="horizontal"
+	class={cn("my-0", className)}
+	{...restProps}
+/>