designtopack/public/site/controllers/site.php

<?php

return function ($page, $kirby, $site) {
  if (!$kirby->user()) {
    go($site->panel()->url());
  }
  $data = $page->toArray();
  $data['template'] = (string) $page->template();

  $userData = [
    "role" => (string) $kirby->user()->role(),
    "uuid" => (string) $kirby->user()->uuid(),
    "notifications" => Yaml::decode($kirby->user()->notifications()->value()),
  ];

  if ($kirby->user()->role() == 'client') {
    $userData['client'] = [
      "name" => (string) $kirby->user()->client()->toPage()->title(),
      "uuid" => (string) $kirby->user()->client()->toPage()->uuid()
    ];
  }

  return [
    'genericData' => $data,
    'userData' => $userData
  ];
};