nx_hash_facade.nx

nx_hash_facade.nx -- unified hash interface. Wraps existing crypto primitives (nx_blake2b, nx_sha512, BLAKE3-when- shipped) behind one substrate-level API. Other primitives that need a content hash call nx_hash_facade_compute() rather than picking a specific algorithm — the facade chooses based on caller's trust ceiling (from nx_attest_silicon). THE STRUCTURAL VALUE: many primitives I've shipped take a `content_hash: nx_size` parameter and rely on the caller to compute it correctly with the "right" algorithm. The facade collapses that decision into one place, so substrate-wide hash discipline is uniform. Composes: nx_blake2b -- the BLAKE2b 64-byte hash primitive (existing) nx_sha512 -- the SHA-512 hash primitive (existing) nx_attest_silicon -- trust-ceiling informs algorithm choice nx_methyl -- content_hash field uses this facade nx_vacuole -- content-addressed storage uses this facade nx_provenance_chain -- output_hash via this facade