v0.4.2

• bdut.h — BDUT_isatty_() uses POSIX fileno() when feature-test macros or a non-strict dialect indicate it is available; otherwise maps stdin/stdout/stderr via STDIN/STDOUT/STDERR_FILENO so strict -std=c11 consumers with -Werror=implicit-function-declaration build cleanly; colour failure output based on stderr TTY state;
• CMakeLists.txt — export package as lowercase bdut-config.cmake under lib/cmake/bdut/ (fixes Linux find_package(BDUT) install-smoke; matches Pantheios/ b64 convention);
• ci.yml, INSTALL.md, README.md, vcpkg — updated install-path / config-file references;
• CMakeLists.txt — CMAKE_C_EXTENSIONS / CMAKE_CXX_EXTENSIONS OFF (ISO -std=c17 / -std=c++23) so CI matches strict consumers such as p99 and surfaces undeclared POSIX calls (e.g. fileno());
• TargetMacros.cmake — apply -Werror / /WX via both C_COMPILER_ID and CXX_COMPILER_ID;