Hooks de cycle de vie

$result = $agent->run(
    input: $prompt,
    client: $client,
    onEvent: function (array $event): void {
        $logger->info("agent event", [
            "type" => $event["type"],
            "run_id" => $event["run_id"],
            "details" => $event["details"] ?? [],
        ]);
    }
);