Fix triple CBOR encoding of Plutus scripts causing error 3116

[Copilot]

Transactions generated by src/mint.ts were rejected by the Cardano node with error 3116 (malformed Plutus scripts) due to triple CBOR encoding of the script in the witness set.

Root cause

UPLC.applyParamsToScript() returns a double CBOR-encoded hex string. Passing that directly to hexToBytes() and then PlutusV3({ bytes }) stores double-CBOR bytes in the script object. The transaction serializer then wraps script.bytes in a CBOR byte string, producing triple encoding — one layer too many.

Fix

Apply UPLC.applySingleCborEncoding() to strip the outer CBOR layer before constructing PlutusV3, so the serializer produces the required double CBOR on-chain.

// Before — triple CBOR when serialized ❌
const scriptHex = UPLC.applyParamsToScript(plutus, [...]);
return new PlutusV3({ bytes: hexToBytes(scriptHex) });

// After — double CBOR when serialized ✓
const scriptHex = UPLC.applySingleCborEncoding(
  UPLC.applyParamsToScript(plutus, [...])
);
return new PlutusV3({ bytes: hexToBytes(scriptHex) });

Same fix applied to the equivalent createScript in src/nft.ts.

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