function execute(
    bytes calldata commands,
    bytes[] calldata inputs,
    uint256 deadline
) external payable;

// 1. 从 Swap API 获取 calldata
const response = await fetch('/swap-api/api/v1/swap', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    tokenIn: '0x...',
    tokenOut: '0x...',
    amountIn: '1000000000000000000',
    tradeType: 0,
    slippage: 0.5,
    recipient: userAddress,
    deadline: 1200
  })
});

const swapData = await response.json();

// 2. 直接发送交易
const tx = await signer.sendTransaction({
  to: swapData.to,      // Universal Router 地址
  data: swapData.data,  // 编码后的 execute() calldata
  value: swapData.value // 原生 KAS 金额（ERC-20 兑换时为 0）
});

[
  "function execute(bytes calldata commands, bytes[] calldata inputs, uint256 deadline) external payable"
]