Handle hash comments in .sun files

## Summary - ignore lines starting with `#` in `.sun` project files - document `#` comment support in config guide ## Testing - `php Sun/vendor/Soup/build_lib.php` - `clang -O3 -o suncli Sun/sun.cpp -ISun/vendor/Soup Sun/vendor/Soup/libsoup.a -std=c++17 -lstdc++ -lstdc++fs -lpthread` - `./suncli --help` ------ https://chatgpt.com/codex/tasks/task_e_68b306394eac8325ae3d0917bc12f471