Add: v5/iccMAX N-channel + MCS support to IccSignatureUtils.h

[xsscx]

Maintainer Summary

2026-03-19 07:18:10 UTC

IccSignatureUtils.h V2 addresses three issues:

1. Noisy debug output on valid profiles — ICC_LOG_DEBUG and ICC_LOG_WARNING calls fired unconditionally on every signature validation, producing spurious stderr output (e.g., ICC_WARN: ColorSpace signature: 0x6e630011 (Unknown) on valid 17-channel v5 profiles).

2. Missing v5/iccMAX dynamic signatures — N-channel (0x6e63xxxx) and MCS (0x6d63xxxx) signatures were not recognized, causing valid v5 profiles to be flagged as "Unknown".

3. Missing MCH A-F — icSigMCHAData through icSigMCHFData (10-15 channel profiles) were absent from both ColorSpaceSignatureToStr() and IsValidColorSpaceSignature().