Enable Symfony 8 compatibility and modernize package constraints for PHP 8.4 integrations

[Copilot]

This package was constrained to Symfony 7-only dependency ranges and PHPUnit 9-era test configuration, which blocked adoption in Symfony 8 / PHP 8.4 projects. This update aligns dependency constraints and test bootstrap/config with current ecosystem expectations while keeping Symfony 7 compatibility.

• Composer platform and framework compatibility

  • Broadened Symfony component constraints from 7.x-only pins to ^7|^8 for bundle integration in both major lines.
  • Kept PHP platform support at >=8.2 (therefore allowing PHP 8.4 consumers).
  • Added explicit runtime dependencies used by code but previously implicit:
    • symfony/http-client-contracts
    • doctrine/collections
    • webmozart/assert

• Test stack modernization

  • Upgraded phpunit/phpunit to ^11.5.50.
  • Updated phpunit.xml.dist to PHPUnit 11 schema semantics (removed legacy bridge-era/removed options, switched source config accordingly).

• Bootstrap and autoload alignment

  • Added autoload-dev mapping for test namespace.
  • Added missing tests/bootstrap.php referenced by PHPUnit config.

• Dependency graph refresh

  • Regenerated composer.lock to reflect the new constraint set and dependency topology.

Example of the key dependency shift:

{
  "require": {
    "symfony/framework-bundle": "^7|^8",
    "symfony/http-kernel": "^7|^8",
    "symfony/http-client-contracts": "^3",
    "doctrine/collections": "^2.2|^3",
    "webmozart/assert": "^1.11|^2"
  },
  "require-dev": {
    "phpunit/phpunit": "^11.5.50"
  }
}