The concrete-terms gate forbids "provenance": the repository asks for the
exact source, field, or identity a value holds. The module records one
commit and whether its tree was dirty, so it and its callers say that.
The toolchain step also has to stay out of the way of the packaging
entry's error-recording test, which fakes the host platform and would
otherwise report the absent Windows compilers rather than the failure it
exercises. The test mocks the probe, as it already does for the release
environment and the signing keychain, and expects the new stage.
