Cross-chain announcements

// Build cross-chain relay (Ethereum)
const send = client.prepareStealthSend(metaAddressHex);
const relay = await client.buildAnnounceWithRelayRequest(send);
await walletClient.sendTransaction({
  to: relay.to,
  data: relay.data,
  value: relay.value,  // Wormhole message fee
});

// Or bundled in sendStealthPayment
await client.sendStealthPayment({
  chain: "ethereum",
  recipient,
  amount: parseEther("0.01"),
  relay: true,
});

// UAB-only scan
const crossOwned = await client.scanCrossChain();

// Unified inbox (native + UAB when configured)
const inbox = await client.scan({
  chains: ["ethereum"],
  includeCrossChain: true,  // default when UAB is deployed
});
// Each output has source: "native" | "uab"