Add Laravel 13 and PHP 8.4/8.5 support

[CrazyBoy49z]

Changes

• add Laravel 13 support via illuminate/contracts ^13.0
• add compatible Testbench, Pest, Larastan and PHPStan dependency ranges for Laravel 12/13
• extend the CI matrix to test PHP 8.4 and PHP 8.5
• add Laravel 12 and Laravel 13 CI coverage

Notes

• the existing php: ^8.2 constraint already allows PHP 8.4 and 8.5, so the package constraint does not need to be widened
• Laravel 13 is tested only on PHP 8.3+ because Laravel 13 itself requires PHP 8.3 or newer
• no production package behavior is changed