兼容官方格式

curl --request POST \
  --url https://BASE_URL/flux/v1/flux-kontext-pro \
  --header 'Content-Type: application/json' \
  --header 'Authorization: Bearer API_KEY' \
  --data '{
  "prompt": "ein fantastisches bild",
  "input_image": "<string>",
  "input_image_2": "<string>",
  "input_image_3": "<string>",
  "input_image_4": "<string>",
  "seed": 42,
  "aspect_ratio": "<string>",
  "output_format": "jpeg",
  "webhook_url": "<string>",
  "webhook_secret": "<string>",
  "prompt_upsampling": false,
  "safety_tolerance": 2
}'