curl --request POST \
  --url https://app.autoposting.ai/api-proxy/posts/{postId}/rewrite \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "instructions": "<string>"
}
'

{
  "success": true,
  "data": {
    "rewrittenText": "Big announcement from Acme Corp — we're shipping something huge. Stay tuned.",
    "original": "Exciting news from Acme! 🚀"
  }
}