curl --request POST \
  --url http://localhost:4000/v1/transactions/broadcast/{transactionId} \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "rpcUrl": "https://api.avax.network/ext/bc/C/rpc"
}'

{
  "success": true,
  "message": "<string>",
  "data": {
    "transactionId": "tx-uuid-abc123",
    "txHash": "0x789...",
    "status": "broadcasted",
    "broadcastedAt": "2024-01-01T12:10:00Z"
  },
  "statusCode": 123,
  "timestamp": "<string>",
  "path": "<string>"
}