- CLAUDE.md: update error handling guidance from fmt.Errorf to coreerr.E()
and document go-io convention for file I/O
- wire/transaction.go: fix TxOutTarget interface compilation — add
encodeTarget/decodeTarget helpers with support for TxOutToKey,
TxOutMultisig, and TxOutHTLC target types
- wire/transaction.go: add HTLC and multisig input encode/decode
(TxInputHTLC, TxInputMultisig) with string encoding helpers
- wire/transaction.go: add asset operation tag constants (40, 49-51)
and reader functions for HF5 confidential asset operations
- consensus/block.go: replace fmt.Errorf with coreerr.E() for
checkBlockVersion and ValidateTransactionInBlock
- chain/ring.go: replace fmt.Errorf with coreerr.E() in GetRingOutputs
- consensus/v2sig_test.go: replace os.ReadFile with coreio.Read
- crypto/*.go: replace all fmt.Errorf and errors.New with coreerr.E()
across keygen, pow, keyimage, signature, and clsag packages
- types/types_test.go: add tests for HashFromHex, PublicKeyFromHex,
IsZero, and String methods (types coverage 74.5% -> 89.1%)
Co-Authored-By: Virgil <virgil@lethean.io>
