feat: self-service user signup (#672)

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

frontend/src/lib/components/ui/dropdown-button/dropdown-button-item.svelte

@@ -0,0 +1,19 @@
+<script lang="ts">
+	import { cn } from '$lib/utils/style.js';
+	import { DropdownMenu as DropdownMenuPrimitive } from 'bits-ui';
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		...restProps
+	}: DropdownMenuPrimitive.ItemProps = $props();
+</script>
+
+<DropdownMenuPrimitive.Item
+	bind:ref
+	class={cn(
+		'data-highlighted:bg-accent data-highlighted:text-accent-foreground relative flex cursor-default items-center gap-2 rounded-sm px-2 py-1.5 text-sm transition-colors outline-none select-none data-disabled:pointer-events-none data-disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0',
+		className
+	)}
+	{...restProps}
+/>