curl --request POST \
  --url https://api.usezombie.com/v1/agents/{agent_id}/proposals/{proposal_id}:reject \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "rejection_reason": "<string>"
}
'

{
  "agent_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "proposal_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "status": "<string>",
  "rejection_reason": "<string>",
  "request_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}