Auto-inlog opent in nieuw tabblad via GET route

Vervangt server action door /api/auto-login GET route zodat
<a target="_blank"> werkt. Server action verwijderd.

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

app/tenants/page.tsx

@@ -3,7 +3,6 @@ import { getSession } from "../../lib/auth";
 import { listAccounts } from "../../lib/platform-db";
 import { createTenant, deleteTenant } from "./actions";
 import { logout } from "./logout";
-import { autoLogin } from "./auto-login";
 
 export default async function TenantsPage({
   searchParams,
@@ -80,16 +79,14 @@ export default async function TenantsPage({
                         {new Date(a.created_at).toLocaleDateString("nl-NL")}
                       </td>
                       <td className="px-4 py-3 text-right">
-                        <form action={autoLogin}>
-                          <input type="hidden" name="account_id" value={a.id} />
-                          <input type="hidden" name="slug" value={a.slug} />
-                          <button
-                            type="submit"
-                            className="text-xs text-blue-600 hover:text-blue-800 dark:text-blue-400 dark:hover:text-blue-300 transition-colors"
-                          >
-                            Inloggen
-                          </button>
-                        </form>
+                        <a
+                          href={`/api/auto-login?account_id=${a.id}&slug=${a.slug}`}
+                          target="_blank"
+                          rel="noopener noreferrer"
+                          className="text-xs text-blue-600 hover:text-blue-800 dark:text-blue-400 dark:hover:text-blue-300 transition-colors"
+                        >
+                          Inloggen ↗
+                        </a>
                       </td>
                       <td className="px-4 py-3 text-right">
                         <form action={deleteTenant}>