Block major version validation covering all hardfork transitions.
Single expectedBlockMajorVersion function handles HF0→HF4.
Co-Authored-By: Charon <charon@lethean.io>
Fix gaps from spec review: sumInputs/checkKeyImages/verifyV1Signatures
for HTLC inputs, complete call-site list for TxOutTarget refactor,
both v1+v2 decoders, function signature changes, block version check
placement, HTLCOrigin naming clarification.
Co-Authored-By: Charon <charon@lethean.io>
Add design for HTLC and multisig transaction type support needed for
hardfork 1 activation at block 10,080. Covers types, wire, and consensus
changes with TxOutTarget interface refactor.
Co-Authored-By: Charon <charon@lethean.io>