Compare every on/off combination of requested Cargo features over the
Boolean-lattice edges, in Gray-code build order, with a matrix index of
configs, edge comparisons and provenance.
Single runs record explicit feature sets as schemaVersion 2 with resolved
defaults and build environments. Edge comparisons stay diagnostic; edges
clean apart from the intended toggle are marked controlled.
Validate with 68 focused tests, CLI fault checks, dry runs, and container
smoke matrices for branch-b pan cases.
AI-assisted-by: muse-spark-1.3-contributor-free