export declare class UpsertEmailSettingsDto {
    smtp_host: string;
    smtp_port: number;
    smtp_username: string;
    smtp_password?: string;
    smtp_encryption: 'ssl' | 'tls';
    from_email: string;
    from_name?: string;
    user_id?: number | null;
}
export declare class SendTestDto {
    to: string;
}