add ScrollBox convenience helper

src/lib/ScrollBox.svelte

@@ -0,0 +1,28 @@
+<!-- @component
+ScrollBox provides a small convenience wrapper for creating a scrollable container.
+This component expects to be used as a direct child of a flex container that typically
+has a constrained height. It applies the necessary CSS styles to ensure that its content
+can scroll properly and that the container expands to the maximum available space within
+the parent flexbox. Typically, a parent might have these Tailwind classes applied:
+`flex h-full`
+
+More complex layouts that should not expand to fill all available space should use
+a custom container with `overflow-auto` and an intentionally constrained height.
+-->
+
+<script lang="ts">
+	import type { ClassValue } from 'svelte/elements';
+
+	interface Props {
+		/** Applies ui-layout-px padding to the scrollable content area (default: false) */
+		padded?: boolean;
+		class?: ClassValue;
+		children?: import('svelte').Snippet;
+	}
+
+	let { padded = false, class: classValue, children }: Props = $props();
+</script>
+
+<div class={['min-h-0 min-w-0 flex-1 overflow-auto', padded && 'p-layout', classValue]}>
+	{@render children?.()}
+</div>