Upload a photo or video and get back a PERSISTENT numeric vault media id (unlike POST /media/upload, whose descriptor is single-use and must be attached to a post or message immediately). OnlyFans only for now -- Fansly's vault model differs, follow-up.

Send either multipart form-data with a file field, OR a JSON body with a file_url (we fetch it server-side) -- exactly one of the two. Optional multipart field / JSON key async: true always returns 202 immediately with a polling URL; left unset, the upload runs inline and returns 200 with the result if it finishes within ~20s (typical for a photo), otherwise falls back to the same 202 + polling response as async: true -- videos regularly need longer than that to transcode. Poll with GET /v1/{account}/media/vault/upload-status/{job_id} for pending/processing/completed/failed. Billed as a write (charged on job creation, refunded automatically if the job fails).