fix(persons): use danger semantic tokens for review error pill

The page-level error pill on /persons/review used raw Tailwind colour
classes (border-red-200, bg-red-50, text-red-600) — bypassing the
project's danger semantic tokens and breaking dark-mode contract. Align
with the rest of the persons domain (and PersonReviewRow's own deleteBtn)
by switching to border-danger / bg-danger/10 / text-danger.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/routes/persons/review/+page.svelte

@@ -31,7 +31,7 @@ const hasResults = $derived(data.persons.length > 0);
 
 	{#if form?.error}
 		<p
-			class="mb-4 rounded border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-600"
+			class="mb-4 rounded border border-danger bg-danger/10 px-3 py-2 text-sm text-danger"
 			role="alert"
 		>
 			{form.error}