buildReleaseTx spends the certificate and writes no token output: the
omission is the burn. The certificate's own dust pays the beacon and the fee,
so a release needs no other coin.
releaseWithBuiltInWallet checks whether the certificate sits in a beacon
transaction. One that arrived by a plain transfer cannot be proven burned
from the beacon history, so the flow publishes an UPD first and releases its
output. Both paths ran on chipnet, and a released name was registered again
after its release confirmed.
checkAvailability now reports a pending release as not available: a REG
broadcast while the release is unconfirmed could be mined beside it and be
void, and the buyer would have paid for nothing.
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