feat(Section): add SectionSeparator component

src/shared/ui/Section/SectionSeparator/SectionSeparator.svelte

@@ -0,0 +1,14 @@
+<!--
+    Component: SectionSeparator
+    A horizontal separator line used to visually separate sections within a page.
+-->
+<script lang="ts">
+import { cn } from '$shared/shadcn/utils/shadcn-utils';
+
+interface Props {
+    class?: string;
+}
+const { class: className = '' }: Props = $props();
+</script>
+
+<div class={cn('w-full h-px bg-swiss-black/5 dark:bg-white/10 my-8 md:my-12', className)}></div>