feat: add helper function for Hunter instances

[andrefelipe18]

This pull request introduces a new global helper function for creating Hunter instances and updates the documentation to reflect this addition. It also modifies the autoload configuration in composer.json to include the new helper file.

Core functionality updates:

• Added a global helper function hunter in src/helpers.php to simplify the creation of Hunter instances for a given model class. This function includes type declarations and error handling for invalid class names.

Configuration changes:

• Updated the composer.json autoload section to include the src/helpers.php file under the files key, ensuring the helper function is automatically loaded.

Documentation updates:

• Updated docs/examples.md to demonstrate the usage of the new hunter helper function alongside the original Hunter::for method. This includes examples of activating inactive users using both approaches. [1] [2] [3]