Checks prerequisites and immutable inputs for supplemental OIDF conformance runs.

This task does not execute the external suite. Use the checked-in profile runners after the check succeeds:

mix lockspire.oidf_conformance --check
bash scripts/conformance/run_phase37_suite.sh
bash scripts/conformance/run_fapi2_suite.sh

The external lane is supplemental maintainer evidence. It is neither formal certification nor a release gate.