[FIX] simulate.html: card BIG + training user_ids array fix

- simulate.html: aggiunta card BIG (10 aziende, 18 fasi) con url
  simulate-nis2-big.php, label BIG in SIM_LABELS, confirm dialog dedicato
- simulate-nis2-big.php: fix training assign user_id → user_ids (array)
  come richiesto da TrainingController::assignCourse()

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

simulate-nis2-big.php

@@ -1307,7 +1307,7 @@ foreach ($COMPANIES as $slug => $comp) {
                 if ($uid) {
                     $assignRes = api('POST', '/training/assign', [
                         'course_id' => $courseId,
-                        'user_id'   => $uid,
+                        'user_ids'  => [$uid],
                         'due_date'  => date('Y-m-d', strtotime('+30 days')),
                     ], $jwt, $orgId);
                     if (!empty($assignRes['success'])) {