Modernize for PHP 8.5/Twig 3/Symfony 7.4 — migrate templating to Twig, refactor DI/tests and add GitHub Actions CI

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Motivation

• Upgrade the bundle to modern PHP and Symfony stacks and remove legacy templating integration to keep compatibility with current projects.
• Replace container-based rendering and legacy APIs with typed services and Twig Environment for clearer DI and testability.
• Move test and tooling setup to recent PHPUnit and GitHub Actions standards.

Description

• Migrated configuration API to the newer TreeBuilder root API in DependencyInjection/Configuration.php and adjusted configuration key names used by the extension.
• Replaced legacy Symfony Templating helper with a Twig-based helper by switching Templating/SocialBarHelper to accept Twig\Environment and rendering @AzineSocialBar/* templates.
• Refactored Templating/SocialBarTwigExtension to extend Twig\Extension\AbstractExtension, expose TwigFunctions, inject the SocialBarHelper service, modernize argument handling, strict typing, and use \InvalidArgumentException on bad input.
• Updated service configuration in Resources/config/services.yml to inject @twig into the helper and wire the extension to use the helper.
• Modernized composer.json to require php:^8.5, Symfony component packages ^7.4, twig/twig:^3, switched autoloading to PSR-4, and updated dev dependencies to PHPUnit 11 and symfony/yaml.
• Revised tests to use PHPUnit\Framework\TestCase, symfony/yaml parsing, and updated assertions and mocks to reflect the new DI and helper wiring in Tests/*.
• Reworked phpunit.xml.dist for PHPUnit 11 schema and updated coverage/source settings, removed old travis.php.ini, and added a GitHub Actions workflow .github/workflows/ci.yml that runs composer validate and PHPUnit.
• Updated README.md to reflect new requirements, installation instructions, configuration examples, CI notes, and upgrade notes.

Testing

• Ran the test suite with vendor/bin/phpunit -c phpunit.xml.dist, and the unit tests completed successfully.
• Added a GitHub Actions workflow that runs composer validate and vendor/bin/phpunit -c phpunit.xml.dist on push and pull_request (CI configuration added).

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Codex Task