fix(security): add CSRF protection to all POST endpoints + contract tests (B2)

CSRF guards added to 16 admin pages that previously accepted POST requests
without token verification (GR-SEC-001): departments, permissions, roles,
settings, tenants, users (create/edit/bulk/tokens), and lang switch.

New contract tests:
- PostEndpointCsrfContractTest: scans all pages/ for POST handlers and
  verifies checkCsrfToken is present (API/data endpoints exempt).
- DatabaseUpdatesContractTest: validates db/updates/ scripts follow naming
  convention and use idempotent SQL patterns (GR-CORE-010).

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

pages/admin/roles/create().php

@@ -4,6 +4,7 @@ use MintyPHP\Buffer;
 use MintyPHP\Http\SessionStoreInterface;
 use MintyPHP\Router;
 use MintyPHP\Service\Access\RoleAuthorizationPolicy;
+use MintyPHP\Session;
 use MintyPHP\Support\Flash;
 use MintyPHP\Support\Guard;
 
@@ -32,6 +33,12 @@ $rolePermissionRepository = app(\MintyPHP\Repository\Access\RolePermissionReposi
 $permissions = $permissionRepository->listActive();
 $selectedPermissionIds = [];
 
+if ($request->isMethod('POST') && !Session::checkCsrfToken()) {
+    Flash::error(t('Form expired, please try again'), 'admin/roles/create', 'csrf_expired');
+    Router::redirect('admin/roles/create');
+    return;
+}
+
 if ($request->hasBody('description')) {
     $dbSession = app(\MintyPHP\Repository\Support\DatabaseSessionRepository::class);
     $transactionStarted = false;