* feat(php): add support for 'off' variable naming convention in AbstractPhpCodegen
* feat(php-laravel): add tests for issue 21334 with API and model definitions
* feat(php-laravel): update variableNamingConvention option in php-laravel help file to include 'off' as a valid value
* feat: enhance variableNamingConvention options to include 'off' and detailed descriptions in documentation
* feat(php): update variableNamingConvention from 'off' to 'original' in AbstractPhpCodegen
* feat: include php-laravel-issue-21334 in workflow triggers for push and pull_request events
