curl --request POST \
  --url http://localhost:3000/api/openapi/auth/token \
  --header 'Content-Type: application/json' \
  --data '
{
  "key_id": "cvz_key_abc123",
  "key_secret": "cvz_secret_xyz789"
}
'

{
  "success": true,
  "data": {
    "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
    "token_type": "Bearer",
    "expires_in": 86400
  }
}