refactor: move person domain components and utils to lib/person/

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

frontend/src/routes/geschichten/+page.svelte

@@ -3,7 +3,7 @@ import { goto } from '$app/navigation';
 import { m } from '$lib/paraglide/messages.js';
 import { plainExcerpt } from '$lib/utils/extractText';
 import { formatDate } from '$lib/utils/date';
-import PersonTypeahead from '$lib/components/PersonTypeahead.svelte';
+import PersonTypeahead from '$lib/person/PersonTypeahead.svelte';
 import type { PageData } from './$types';
 
 let { data }: { data: PageData } = $props();