Upgrade to Laravel 10+ and PHP 8.1+ with modern tooling

[designvoid]

Summary

This PR modernizes the package by upgrading minimum requirements to PHP 8.1+ and Laravel 10.x, while adding GitHub Actions CI/CD and improving code quality standards.

Key Changes

• PHP & Laravel Requirements: Updated minimum PHP version to 8.1 and added support for Laravel 10.x, 11.x, and 12.x
• CI/CD Migration: Replaced Travis CI with GitHub Actions workflow that tests against PHP 8.1-8.3 and Laravel 10-12 combinations
• Code Quality:
  • Added declare(strict_types=1) to all source files
  • Added proper type hints and return type declarations throughout
  • Updated all handler classes with explicit exception type hints
  • Improved property type declarations with nullable types
• Configuration Updates:
  • Updated Scrutinizer CI config to use PHP 8.2 and proper coverage file naming
  • Enhanced StyleCI config with risky mode enabled
  • Removed deprecated .travis.yml
• Dependencies: Updated composer.json with explicit Laravel framework dependencies and modern test tooling (PHPUnit 10+, Testbench 8-10)
• PHPUnit Config: Modernized phpunit.xml to use current schema and best practices
• Documentation: Updated README with new requirements, modern code examples, and upgrade guide from 2.x

Implementation Details

• All exception handlers now properly type-hint their exception parameters
• Status codes are consistently cast to strings per JsonAPI specification
• Return types use union types (ErrorHandledInterface|ErrorHandledCollectionInterface)
• Improved null safety with proper nullable type declarations
• GitHub Actions matrix tests all supported PHP/Laravel combinations with proper exclusions for incompatible versions

https://claude.ai/code/session_01D66jVcfUoruENdy4YFLxPo