C++ build configuration for core CLI project detection and future
`core compile` command. Defines Conan dependencies, CMake settings,
cross-compilation targets, and packaging options.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Build system extracted to host-uk/build and wired in as a git
submodule following the core CLI convention (.core/<tool>/).
- CMake modules, cross-compilation profiles now from .core/build/cmake/
- Conan credentials read from environment instead of hardcoded
- Removed cmake/ directory (14 files) — all now in submodule
- Makefile, CMakeLists.txt, CMakePresets.json updated for new paths
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>