build: auto-detection
hetrix inspects the repo and picks the right build system.
detection order
CMakeLists.txt -> meson.build -> configure[.ac] -> Makefile -> Cargo.toml -> go.mod -> build.zig -> dune-project -> pyproject.toml / setup.py -> package.json -> *.gemspec -> *.cpp files -> *.c files
manual override
set "build": "system" in index.json to force a specific builder.