[Platform] Exposing clients to the container

[Guikingone]

Hi 👋🏻

Small suggestion for future developments regarding the Platform, for now, clients are not exposed through the container as they're built using the *PlatformFactory (example via Ollama):

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\AI\Platform\Bridge\Ollama;

use Psr\EventDispatcher\EventDispatcherInterface;
use Symfony\AI\Platform\Bridge\Ollama\Contract\OllamaContract;
use Symfony\AI\Platform\Contract;
use Symfony\AI\Platform\ModelCatalog\ModelCatalogInterface;
use Symfony\AI\Platform\Platform;
use Symfony\Component\HttpClient\EventSourceHttpClient;
use Symfony\Contracts\HttpClient\HttpClientInterface;

/**
 * @author Christopher Hertel <mail@christopher-hertel.de>
 */
final class PlatformFactory
{
    public static function create(
        string $hostUrl = 'http://localhost:11434',
        ?HttpClientInterface $httpClient = null,
        ModelCatalogInterface $modelCatalog = new ModelCatalog(),
        ?Contract $contract = null,
        ?EventDispatcherInterface $eventDispatcher = null,
    ): Platform {
        $httpClient = $httpClient instanceof EventSourceHttpClient ? $httpClient : new EventSourceHttpClient($httpClient);

        return new Platform(
            [new OllamaClient($httpClient, $hostUrl)],
            [new OllamaResultConverter()],
            $modelCatalog,
            $contract ?? OllamaContract::create(),
            $eventDispatcher,
        );
    }
}

Once in the bundle, only the platform can be accessed, this approach lock the capacity to interact with the client (for decoration purposes mostly, can be useful for #943 and more) and even if the Platform is a good entry point, sometimes, we might need to interact with the client rather than the platform (which is a bit "too late" in the call chain).

Could clients be exposed in the container, maybe via a new definition during the platform building phase?