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/login/actions.ts

@@ -0,0 +1,15 @@
+"use server";
+
+import { redirect } from "next/navigation";
+import { getUserByEmail, verifyPassword, createSession } from "../../lib/auth";
+
+export async function login(formData: FormData) {
+  const email = formData.get("email") as string;
+  const password = formData.get("password") as string;
+  const user = getUserByEmail(email);
+  if (!user || !verifyPassword(password, user.password_hash)) {
+    redirect("/login?error=1");
+  }
+  await createSession({ userId: user.id, email: user.email, name: user.name });
+  redirect("/tenants");
+}