Adds three exact targets (linux-x86_64, linux-aarch64, macos-arm64) at 1.2.2-sol.2 with artifact and companion-manifest identities and exact seven-member inventories. Includes an import-time validator and a platform resolver independent of probe.normalize_solstone_core_machine so Darwin aarch64 is rejected. Adds the generated JSON mirror that ships in every root wheel via graft solstone, and wires make check-nvattest-authority into install-checks. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>