fix: replace hardcoded bg-white/border-brand-sand/text-brand-navy with semantic tokens in dashboard widgets

All four dashboard components (ResumeStrip, Mentions, NeedsMetadata, RecentDocuments)
used static brand colors that do not adapt to dark mode. Replace with bg-surface,
border-line, text-ink, text-ink-2 throughout.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/components/DashboardNeedsMetadata.svelte

@@ -12,27 +12,22 @@ let { incompleteDocs }: Props = $props();
 </script>
 
 {#if incompleteDocs.length > 0}
-	<div
-		data-testid="dashboard-needs-metadata"
-		class="border-brand-sand rounded-sm border bg-white p-6"
-	>
+	<div data-testid="dashboard-needs-metadata" class="rounded-sm border border-line bg-surface p-6">
 		<h2 class="mb-4 font-sans text-xs font-bold tracking-widest text-gray-400 uppercase">
 			Metadaten fehlen
 		</h2>
 		{#each incompleteDocs as doc (doc.id)}
-			<div class="border-brand-sand flex items-center border-b py-2 last:border-0">
+			<div class="flex items-center border-b border-line py-2 last:border-0">
 				<a
 					href="/enrich/{doc.id}"
-					class="font-serif text-sm text-ink hover:text-brand-navy hover:underline"
+					class="font-serif text-sm text-ink hover:text-ink-2 hover:underline"
 				>
 					{doc.title}
 				</a>
 			</div>
 		{/each}
 		<div class="mt-4">
-			<a href="/enrich" class="font-sans text-xs text-brand-navy/60 hover:text-brand-navy">
-				Alle anzeigen
-			</a>
+			<a href="/enrich" class="font-sans text-xs text-ink-2 hover:text-ink"> Alle anzeigen </a>
 		</div>
 	</div>
 {/if}