Release was the one escrow spend path still hardwired to the synthetic
testTxBody backend, so suppliers had no way to resolve Submitted escrows
past the accept window on mainnet (the sweeper parks them 'for supplier
Release'). Adds buildLiveTxForRelease mirroring the Reclaim builder
(supplier payout, Constr4/tag 125 redeemer, Ogmios UPLC eval) and the
detectCborBackend dispatch in buildReleaseTx, reclaim.ts-style.
validFrom clamps to submitted_at + ACCEPT_WINDOW rather than tip-60s
alone: the back-pad by itself violates the validator whenever the tip is
less than 60s past the window.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
