Summary

Updates CMake configuration to:

• Properly detect C++20 concepts support
• Define appropriate macros (THREAD_HAS_COMMON_CONCEPTS)
• Ensure CI/CD workflows use compatible compilers

Parent Issue

Part of #271

Tasks

• Update ThreadSystemFeatures.cmake for concepts detection
• Add THREAD_HAS_COMMON_CONCEPTS definition when common_system is available
• Verify GCC 10+, Clang 10+, MSVC 2019 16.3+ support

Related Files

• cmake/ThreadSystemFeatures.cmake
• .github/workflows/