feat(license): warn admins when no download key is configured

Adds onAfterRoute hook that checks the update site for a valid
MOKO-XXXX license key and shows a warning message once per session
if missing — directs users to System > Update Sites.

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

src/packages/plg_system_mokojoomcross/src/Extension/MokoJoomCross.php

@@ -34,10 +34,20 @@ class MokoJoomCross extends CMSPlugin implements SubscriberInterface
     public static function getSubscribedEvents(): array
     {
         return [
+            'onAfterRoute'  => 'onAfterRoute',
             'onAfterRender' => 'onAfterRender',
         ];
     }
 
+    public function onAfterRoute(): void
+    {
+        $app = $this->getApplication();
+
+        if ($app->isClient('administrator')) {
+            $this->warnMissingLicenseKey();
+        }
+    }
+
     /**
      * Process queued posts on page load (backend and/or frontend).
      *
@@ -83,6 +93,59 @@ class MokoJoomCross extends CMSPlugin implements SubscriberInterface
         \Joomla\Component\MokoJoomCross\Administrator\Helper\QueueProcessor::processQueue(5);
     }
 
+    /**
+     * Warn administrators once per session when no license key is configured.
+     *
+     * @return  void
+     */
+    private function warnMissingLicenseKey(): void
+    {
+        $session = Factory::getSession();
+
+        if ($session->get('mokojoomcross.license_warned', false)) {
+            return;
+        }
+
+        $user = Factory::getUser();
+
+        if ($user->guest || !$user->authorise('core.manage')) {
+            return;
+        }
+
+        $session->set('mokojoomcross.license_warned', true);
+
+        try {
+            $db = Factory::getDbo();
+
+            $query = $db->getQuery(true)
+                ->select($db->quoteName('extra_query'))
+                ->from($db->quoteName('#__update_sites'))
+                ->where($db->quoteName('name') . ' = ' . $db->quote('MokoJoomCross Updates'))
+                ->setLimit(1);
+            $db->setQuery($query);
+            $extraQuery = (string) $db->loadResult();
+
+            if (!empty($extraQuery)) {
+                parse_str($extraQuery, $parsed);
+
+                if (!empty($parsed['dlid']) && preg_match('/^MOKO-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}$/', $parsed['dlid'])) {
+                    return;
+                }
+            }
+
+            $this->getApplication()->enqueueMessage(
+                '<strong>Moko Consulting License Key Required</strong> — '
+                . 'No download key is configured. Updates will not be available until a valid license key is entered. '
+                . 'Go to <a href="index.php?option=com_installer&view=updatesites">System → Update Sites</a> '
+                . 'and enter your license key (<code>MOKO-XXXX-XXXX-XXXX-XXXX</code>) in the Download Key field '
+                . 'for the MokoJoomCross update site.',
+                'warning'
+            );
+        } catch (\Throwable $e) {
+            // Don't break admin over a license check
+        }
+    }
+
     /**
      * Store the last page-load run timestamp.
      */