feat: add company management and user-company assignment in admin panel

shop/app/admin/einstellungen/page.tsx

@@ -169,6 +169,7 @@ export default function AdminSettings() {
               <thead>
                 <tr className="border-b border-slate-200 dark:border-white/10 text-slate-400 text-xs font-semibold uppercase">
                   <th className="pb-3">Partner E-Mail</th>
+                  <th className="pb-3">Firma</th>
                   <th className="pb-3">Status</th>
                   <th className="pb-3">Erstellt am</th>
                   <th className="pb-3 text-right">Aktionen</th>
@@ -186,6 +187,9 @@ export default function AdminSettings() {
                         {partner.email}
                       </div>
                     </td>
+                    <td className="py-4 text-sm text-slate-700 dark:text-slate-300">
+                      {partner.company_name || '–'}
+                    </td>
                     <td className="py-4">
                       {isGesperrt ? (
                         <span className="inline-flex items-center gap-1.5 px-2.5 py-0.5 rounded-full text-xs font-medium bg-red-100 text-red-700 dark:bg-red-500/10 dark:text-red-400 border border-red-200 dark:border-red-500/20">