txbuild.py gets real: make_ogmios_context builds an
OgmiosChainContext pointed at 127.0.0.1:1337 by default (matches the
Rackham stack), get_protocol_parameters peeks at live params,
get_address_utxos powers the eventual refund path, submit_signed_tx
ships a cold-signed blob to the chain.
mint.py's mint_nft_cert now constructs the real tx body:
- mints exactly 1 of {policy_id}.{asset_name}
- sends it to recipient_address in its own UTxO padded with min-ADA
- attaches CIP-25 v2 metadata + the native script as aux data
- clamps TTL to policy.locked_after_slot when the policy is time-locked
Does NOT sign — matches the ADAMaps cold-signing pattern. Returns an
UnsignedMint bundle carrying body CBOR, aux CBOR, native-script CBOR,
required-signer hashes, and a human-readable summary. Operator moves
the bundle to the cold host (Lucy in Sulkta's pattern — 2-of-2
native-script under Cobb + Kayos skeys), signs offline, ships the
signed CBOR back. submit_signed_tx finishes the round-trip.