- Add Primaries.Unspecified (value 2) per user request and H.273 spec
- Rename Primaries value 0 from Unspecified to Reserved for spec accuracy
- Rename Transfer value 0 from Unspecified to Reserved for consistency
- Simplify Transfer value 2 from Unspecified_Image to Unspecified
- Update condition check to use enum values instead of numeric tuple
- Enhance docstring with detailed sources and rationale for changes
All CICP values verified against ITU-T H.273, ISO/IEC 23091-2, H.264/H.265 specifications, and FFmpeg AVColorPrimaries/AVColorTransferCharacteristic enums.