fix: require GitLab client config at server startup

    let cluster_health = ClusterHealthChecker::new(config.health_check_url.clone()).into_arc();

    let resolver_registry = config

        .gitlab_client_config()

        .map(|cfg| {

            let client = gitlab_client::GitlabClient::new(cfg)

    let gitlab_client_config = config.gitlab_client_config().ok_or_else(|| {

        anyhow::anyhow!(

            "GitLab client config is required: set gitlab.base_url and provide \

             the JWT signing key (via config or /etc/secrets/gitlab/jwt/signing_key)"

        )

    })?;

    let client = gitlab_client::GitlabClient::new(gitlab_client_config)

        .map(Arc::new)

        .map_err(|e| anyhow::anyhow!("failed to create GitlabClient: {e}"))?;

    let mut registry = content::ColumnResolverRegistry::new();

        "gitaly",

        Arc::new(content::gitaly::GitalyContentService::new(client)),

    );

            Ok::<_, anyhow::Error>(Arc::new(registry))

        })

        .transpose()?;

    if resolver_registry.is_some() {

    let resolver_registry = Some(Arc::new(registry));

    info!("Content resolution enabled (GitlabClient configured)");

    } else {

        info!("Content resolution disabled (no GitLab client config)");

    }

    let graph_client = config.graph.build_client();

    let http_server = HttpServer::bind(config.bind_address, graph_client).await?;