Update Entrust.php

[itashia]

Improvements Summary

• Added precise type hints for parameters and return types (e.g. ?Authenticatable, void)
• Used modern PHP features like nullsafe operator (?->) and arrow functions
• Reduced code duplication with helper methods (registerRouteFilter, generateFilterName)
• Centralized access handling in handleRouteAccessCheck
• Improved readability with clearer comments, formatting, and naming
• Maintained full backward compatibility with no behavior changes or new dependencies