curl --request POST \
  --url https://open.skills.video/api/v1/generation/xai/grok-imagine-video/extend-video \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "<string>",
  "video_url": "<string>"
}
'

{
  "id": "<string>",
  "status": "starting",
  "usage": {
    "total": 0,
    "subscription": 0,
    "permanent": 0
  }
}