transfer package

VoucherSymbol returns the grc20 token symbol for an IBC voucher denom: the IBC hash truncated to grc20's MaxSymbolLen. The full voucherDenom ("ibc/<64-hex- hash>") can't be a symbol because v2 grc20 enforces MaxSymbolLen and [A-Za-z0-9_-] only. Since grc20reg keys tokens by rlmpath.symbol, this is also the symbol component of a voucher's registry key, so callers locate a voucher via grc20reg.Get(<this realm's pkgpath> + "." + VoucherSymbol(ibcDenom)).