nx_gcode_manifest_test.nx

nx_gcode_manifest_test.nx -- exercise manifest emit + finalize + determinism on synthetic blobs. Closed-form invariants: (a) Fresh manifest contains the magic line. (b) After add_blob x 4, the buffer grew + non-empty. (c) Finalize sets finalized=1 and appends the self-hash line. (d) Post-finalize, add_blob returns -2 (refused). (e) Two manifests built with the same inputs produce byte-identical buffers (determinism for reproducible builds). (f) Tampering with the buffer breaks the self-attestation: recomputing blake2b over the pre-final bytes no longer matches the embedded final hash. expect_exit: 0 license_tier: ORIGINAL