The address to hand out: the onchain address for boarding, the Arkade
address for default.
Not always contract.address. A boarding row persists the ark
encoding of its script, so reading contract.address on a boarding
entry yields an address no onchain sender can pay.
The persisted, watched contract row — script, type, state and metadata.
The descriptor this address was derived from — hand it to
signerForDescriptor to recover the key later. Every entry from a
single call carries the same one, because they share an index.
Also present on contract.metadata.signingDescriptor, but surfaced here
typed: Contract.metadata is Record<string, unknown>, so reading it
there costs the caller an as string on the one field they are most
likely to persist beside an invoice.
One minted address and the contract row backing it.