feat: contacts and voucher assignment

app/vouchers/[id]/page.tsx

@@ -15,6 +15,7 @@ type Voucher = {
   kategorie: string | null;
   notiz: string | null;
   status: string;
+  contacts?: { contact: { id: number; name: string; email: string | null; telegramChatId: string | null } }[];
 };
 
 export default function VoucherDetailPage({ params }: { params: Promise<{ id: string }> }) {
@@ -62,6 +63,9 @@ export default function VoucherDetailPage({ params }: { params: Promise<{ id: st
         {v.codeText && <div><dt className="font-medium">Code</dt><dd>{v.codeText}</dd></div>}
         {v.kategorie && <div><dt className="font-medium">Kategorie</dt><dd>{v.kategorie}</dd></div>}
         {v.notiz && <div><dt className="font-medium">Notiz</dt><dd>{v.notiz}</dd></div>}
+        {v.contacts && v.contacts.length > 0 && (
+          <div><dt className="font-medium">Empfänger</dt><dd>{v.contacts.map((c) => c.contact.name).join(", ")}</dd></div>
+        )}
       </dl>
       {v.status !== "eingeloest" && (
         <button onClick={redeem} className="rounded bg-black px-4 py-2 text-white">