Run tests on PHP 8.5 and update test environment

[clue]

Builds on top of #84, reactphp/socket#325, reactphp/promise#264, reactphp/event-loop#282, and clue/framework-x#297

[Copilot]

Pull request overview

This PR updates the test environment to support PHP 8.5 and makes necessary compatibility adjustments for modern PHP versions.

Changes:

• Add PHP 8.5 to the CI test matrix
• Update CI environment from Ubuntu 22.04 to 24.04 and GitHub Actions checkout from v4 to v6
• Update ReactPHP dependencies to newer minor versions (event-loop ^1.6, promise ^3.3, socket ^1.17)
• Fix ReflectionProperty usage for PHP 8.1+ compatibility by conditionally calling setAccessible()

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
.github/workflows/ci.yml	Adds PHP 8.5 to test matrix, updates Ubuntu to 24.04, and updates checkout action to v6
composer.json	Updates ReactPHP dependencies to newer minor versions supporting PHP 8.5
tests/FactoryTest.php	Adds PHP 8.1+ compatibility fix for ReflectionProperty by conditionally calling setAccessible()

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