Upgrade to PHP 8.5 and apply Rector cleanup

Goal

Upgrade PHP runtime to 8.5, update Composer dependencies, and apply Rector cleanup.

What needs to be done

• Bump composer.json PHP constraint to ^8.5, run composer update
• Update Dockerfile(s)/docker-compose and CI to PHP 8.5
• Add rector/rector: ^2.4, add rector.php:

  return RectorConfig::configure()
      ->withPaths([__DIR__.'/bin', __DIR__.'/config', __DIR__.'/src', __DIR__.'/tests'])
      ->withPhpSets()
      ->withComposerBased(doctrine: true, symfony: true, phpunit: true)
      ->withAttributesSets(doctrine: true, symfony: true, phpunit: true)
      ->withSkip([
          \Rector\Php84\Rector\MethodCall\NewMethodCallWithoutParenthesesRector::class,
          \Rector\Php84\Rector\Class_\DeprecatedAnnotationToDeprecatedAttributeRector::class,
      ]);
  

• Apply rector, fix what it can't (implicit nullable params, __sleep/__wakeup, removed functions like xml_parser_free())
• Full test suite + static analysis green on PHP 8.5

Start with composer.json, the Dockerfile(s), docker-compose configuration, and CI configuration to map the PHP 8.5 upgrade. Add the requested rector.php configuration, then apply Rector across bin, config, src, and tests and review the listed compatibility fixes. Done means Composer dependencies are updated and the full test suite plus static analysis are green on PHP 8.5.