Fix three bugs in the v2+ wire format and add complete variant tag handlers
for Zarcanum proof and signature structures. Verified byte-identical
round-trip against a real post-HF4 coinbase transaction from testnet block
101 (1323 bytes, tx hash 543bc3c2...3b61e0).
Bugs fixed:
- V2 suffix order was attachment+proofs, corrected to attachment+signatures+proofs
- TransactionHash was hashing full blob, corrected to prefix-only (matching C++)
- tagSignedParts was reading 4 fixed bytes, corrected to two varints
New: TxInputZC type, SignaturesRaw field, tagZarcanumTxDataV1 handler,
proof tags 46-48, signature tags 42-45, crypto blob readers for BPP/BPPE/
BGE/CLSAG GGX/GGXXG/aggregation proof/double Schnorr structures.
Co-Authored-By: Charon <charon@lethean.io>
8335b11a85