nx_doc_vault.nx

nx_doc_vault.nx -- LEGAL RUNG D1: per-tenant document vault (retention core). module: nishi-core.legal.doc_vault capability: LEGAL_DOC_VAULT The storage + audit home for D5 seals, encoding the registry's retention requirements as invariants BY CONSTRUCTION: ADDITIVE-ONLY (Rule 13) -- a new version never overwrites or removes an old one; soft-delete only demotes is_current. History is sacred. SINGLE AUTHORITATIVE COPY -- exactly one is_current=1 per doc (UETA Section 16) = the authoritative copy. VERSIONED + TAMPER-EVIDENT -- each version links prev_hash == (UETA Section 12) prior version's content_hash, so any alteration of a non-final version breaks the chain (the I/O layer adds recompute-SHA256-vs-stored for the final version). PER-TENANT ISOLATION -- vault index lives at the tenant's (MRPC 1.6 confidentiality) private prefix <base><tid>.docvault; tenant-id validated [A-Za-z0-9_-] only (no '.'/'/' -> no cross-tenant traversal), the proven nx_vizsla_tenant discipline. Representation: a flat i64 record array (caller-allocated; substrate scale- agnostic, no internal allocation) -- record r, field f at flat[r*VF_STRIDE+f]. content_hash is an i64 in this logic core; the I/O layer stores the full SHA-256 digest and the chain comparison is identical. Composes: nx_syscalls (tenant-id validation). Distinct from nx_vizsla_tenant because: that shards CONTACTS/relate data; this shards VERSIONED DOCUMENTS with a tamper-evident chain. license_tier: ORIGINAL lineage_id: nishi_doc_vault_d1