Fix login redirect — access result.data.token/user

Login/register pages now correctly unwrap API response {data: {token, user}}.
Cleaned up leftover apiFetch code.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/app/register/page.tsx

@@ -29,7 +29,7 @@ export default function RegisterPage() {
         name: name.trim(),
         phone: phone.trim() || undefined,
       });
-      setAuth(result.token, result.user);
+      setAuth(result.data.token, result.data.user);
       router.push("/tasks");
     } catch (err) {
       setError(err instanceof Error ? err.message : "Chyba registrace");