Produce a piece of music from a text description, such as "epic orchestral battle theme" or "calm piano melody", with optional lyrics. The job result is a single audio result containing a URL. The description field is required; duration must be one of the allowed values (0 means auto, otherwise multiples of 10 up to 180 seconds) and out-of-range values return HTTP 400. Credits are held when the job is accepted and refunded if it fails or is cancelled. Use this for songs and musical scores; use createSoundEffect for short sound effects, createAmbiance for looping background soundscapes, and createAudioTransform to remix an existing audio sample. Pass an optional request_id to tag the result so you can locate it later via listGenerations (type audio). Requires an API key (user scope). The call returns 202 with a job id - poll getApiJob (pass wait 30 to long-poll) honouring poll_after_ms, until status is succeeded; its result field is exactly the response documented for this operation. Synchronous responses are deprecated but still supported: pass `async: false` to block until the result is ready and receive it as the response body. Synchronous calls run on the same queue: the response carries an X-Ludo-Job-Id header, and a job still running after 15 minutes comes back as 202 with the job instead of an error. Each account may have up to 50 generations queued or running at once via the API; a request beyond that returns 429 (code PENDING_JOBS_LIMIT).