It looks like `spin build` does `meson build` and `meson install` and doesn't do `pip install`. I'd like numpy to be importable in a python environment of my choosing, so I tend to instead manually install numpy into that environment by invoking pip with something like `python -m pip install . -v --no-build-isolation -Cbuilddir=build -C'compile_args=-v' -C'setup_args=-Dbuildtype=debug'. I like seeing the compile command meson uses, so I pass in `-v` through meson's `compile_args` and I often need a debug build, so I set the build type manually as well.