Fix critical bugs breaking ticket page and settings modal

- Fix fatal PHP error in UserModel::getAllGroups() - typo 'setCache'
  should be 'setCached', was causing ticket page to fail to render
- Fix settings.js null reference errors when timezone element missing
  on ticket page (only exists on dashboard)
- Fix ESC key detection for settings modal (checked 'block' but modal
  uses 'flex' display)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

models/UserModel.php

@@ -302,7 +302,7 @@ class UserModel {
         sort($uniqueGroups);
 
         // Cache the result
-        self::setCache($cacheKey, $uniqueGroups);
+        self::setCached($cacheKey, $uniqueGroups);
 
         return $uniqueGroups;
     }