Delta gasless intent swaps

# 1. Get a Delta quote (returns a delta block: route + alternatives + spender)
curl -s "https://api.velora.xyz/v2/quote" \
  --data-urlencode "srcToken=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE" \
  --data-urlencode "destToken=0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48" \
  --data-urlencode "amount=1000000000000000000" \
  --data-urlencode "srcDecimals=18" \
  --data-urlencode "destDecimals=6" \
  --data-urlencode "side=SELL" \
  --data-urlencode "chainId=1" \
  --data-urlencode "mode=DELTA" \
  --data-urlencode "userAddress=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" \
  --data-urlencode "partner=my-app-name" \
  -G -o quote.json

# 2. Build the order from the quote's delta.route (returns toSign + orderHash)
jq --argjson deadline "$(($(date +%s) + 1800))" \
   '{route: .delta.route,
     owner: "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
     deadline: $deadline,
     partner: "my-app-name"}' quote.json > build.json
curl -X POST "https://api.velora.xyz/v2/delta/orders/build" \
  -H "Content-Type: application/json" -d @build.json

# 3. Sign the returned toSign with the user's wallet (ERC-2098 compact)
#    and write the order + signature to signed.json

# 4. Submit the signed order
curl -X POST "https://api.velora.xyz/v2/delta/orders" \
  -H "Content-Type: application/json" -d @signed.json

# 5. Poll status
curl "https://api.velora.xyz/v2/delta/orders/{orderId}"