Fix server action structuur in login en tenants pagina's

Inline server actions in page components veroorzaken runtime errors.
Verplaatst naar aparte actions.ts / logout.ts bestanden.

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

app/tenants/page.tsx

@@ -1,7 +1,8 @@
 import { redirect } from "next/navigation";
-import { getSession, destroySession } from "../../lib/auth";
+import { getSession } from "../../lib/auth";
 import { listAccounts } from "../../lib/platform-db";
 import { createTenant, deleteTenant } from "./actions";
+import { logout } from "./logout";
 
 export default async function TenantsPage({
   searchParams,
@@ -28,13 +29,7 @@ export default async function TenantsPage({
           <span className="font-semibold text-zinc-900 dark:text-zinc-100">Rikx Beheer</span>
           <div className="flex items-center gap-4">
             <span className="text-sm text-zinc-500">{session.email}</span>
-            <form
-              action={async () => {
-                "use server";
-                await destroySession();
-                redirect("/login");
-              }}
-            >
+            <form action={logout}>
               <button className="text-sm text-zinc-500 hover:text-zinc-900 dark:hover:text-zinc-100 transition-colors">
                 Uitloggen
               </button>