Allow securing the task runner

[Vectorial1024]

Currently, the task runner can be manually called with a correctly crafted command instruction. This is supposedly different from Laravel 11's new Concurrency module, which runs the task in a hidden Artisan command.

This allows attackers to just input whatever stuff into the command line to run arbitrary code.

We have 2 options:

• Try to understand how this Concurrency module handles "hidden Artisan commands", and learn from them; or
• Add a way for this library to verify the runner instruction is sent from itself, and is not from an outsider

[Vectorial1024]

It is possible to hide Artisan commands; see https://laravel-news.com/hiding-console-commands .

[Vectorial1024]

We can delegate the verification to opis/closure since that library forms the core of this library's functionality.