Modify: vcpkg add Json Lib & Tools

[xsscx]

PR Summary

#943

What Changed

• Adds JSON support to the vcpkg feature model.
• Keeps the vcpkg port static-only via vcpkg_check_linkage(ONLY_STATIC_LIBRARY).
• Moves feature behavior into upstream CMake options instead of patching CMake files inside the vcpkg port.
• Makes XML, JSON, and tools opt-in features.
• Updates exported CMake package behavior so consumers can link the expected RefIccMAX::* targets.
• Updates the hello-world vcpkg example to consume iccdev with XML and JSON features.
• Adds usage guidance for downstream find_package(RefIccMAX CONFIG REQUIRED) consumers.
• Updates CI workflows to validate the vcpkg port and shared export consumer path across supported platforms.

Developer Impact

After this PR, downstream users can install:

• iccdev provides the core static library.
• iccdev[xml] enables XML library support.
• iccdev[json] enables JSON library support.
• iccdev[tools,xml,json] enables the command-line tooling path with XML and JSON tools.

Consumers can continue to use target-based CMake linkage:

find_package(RefIccMAX CONFIG REQUIRED)
target_link_libraries(my_app PRIVATE RefIccMAX::IccProfLib2)
target_link_libraries(my_app PRIVATE RefIccMAX::IccXML2)
target_link_libraries(my_app PRIVATE RefIccMAX::IccJSON2)

Checklist

• Built locally with the documented build flow in docs/build.md
• Ran relevant profile tests (Testing/CreateAllProfiles.* and Testing/RunTests.*)
• Added or updated regression coverage for behavior changes
• Checked sanitizer coverage for memory-safety or parser changes
• Updated documentation for user-visible behavior changes
• New source files include the ICC copyright and BSD 3-Clause license header
• Code style matches nearby code: 2-space indent, K&R braces, m_ members