Function calculateDummySongUsage

Returns {
    completion_tokens: number;
    completion_tokens_details?: {
        accepted_prediction_tokens: number;
        audio_tokens: number;
        reasoning_tokens: number;
        rejected_prediction_tokens: number;
    };
    prompt_tokens: number;
    prompt_tokens_details?: { audio_tokens: number; cached_tokens: number };
    total_tokens: number;
}