CI4MS Fileeditor allows deletion and rename of critical application files due to missing extension allowlist on destructive operations

CI4MS is a CodeIgniter 4-based content management system skeleton. Prior to version 0.31.9.0, the Fileeditor module enforces an extension allowlist (`['css','js','html','txt','json','sql','md']`) on content-write operations (`saveFile`, `createFile`), but two destructive endpoints — `deleteFileOrFolder` and `renameFile` — never validate the extension of the *source* path. A backend user with file-editor permissions can therefore unlink or rename any file inside the project root that is not explicitly listed in the small `$hiddenItems` blocklist. Critical framework files such as `app/Config/Routes.php`, `app/Config/App.php`, `app/Config/Database.php`, `app/Config/Filters.php`, `public/index.php`, and `public/.htaccess` all live outside that blocklist and can be destroyed, producing a persistent denial of service that requires filesystem-level redeployment to recover. Version 0.31.9.0 patches the issue.