Optionalblock_height?: numberOptionalvinInputs as returned by Esplora's /address/:addr/txs, each carrying the
outpoint it spends (txid:vout). Optional: not every provider populates
it (the electrum provider omits inputs), so consumers that correlate
spenders must tolerate its absence. Used to recover a boarding output's
spending (commitment) tx when /outspends omits the spender txid.
Set by Esplora; the electrum provider omits it.