Build standalone Sparse and Smatch from recorded revisions, applying the
reviewed SCST Smatch frontend correction. Install matching native Smatch
data without replacing standalone Sparse or adding project models.
Reuse the existing checksum-pinned kernel headers. Record source
commits, patch and binary hashes, and installed model contents for CI
evidence. Fail preparation instead of silently falling back to different
tools; no SCST modules are built or loaded while preparing this image.
