fix: replace remaining hardcoded brand-navy/white tokens with semantic tokens

Fixes dark mode in enrich/done page (bg-white → bg-surface, text-brand-navy → text-ink,
border-brand-sand → border-line), enrich/[id] skip button (text-brand-navy/60 → text-ink-2),
and PanelHistory version list (divide-brand-sand → divide-line).

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

frontend/src/routes/enrich/[id]/+page.svelte

@@ -135,7 +135,7 @@ let selectedReceivers = $state(untrack(() => doc.receivers ?? []));
 				<button
 					type="submit"
 					form="skip-form"
-					class="font-sans text-sm font-medium text-brand-navy/60 transition-colors hover:text-brand-navy"
+					class="font-sans text-sm font-medium text-ink-2 transition-colors hover:text-ink"
 				>
 					{m.enrich_skip()}
 				</button>