fix: lagg till SessionProvider i root layout sa useSession() fungerar

frontend/app/Providers.tsx

@@ -0,0 +1,7 @@
+'use client';
+
+import { SessionProvider } from 'next-auth/react';
+
+export default function Providers({ children }: { children: React.ReactNode }) {
+  return <SessionProvider>{children}</SessionProvider>;
+}