nx_doc_envelope_gate.nx

nx_doc_envelope_gate.nx -- GATE for LEGAL D2 (nx_doc_envelope). Drives the e-signature ENVELOPE workflow composing D0 (compliance) + D1 (vault) + D5 (real Ed25519 seal over the RFC 8032 KAT keypair) and asserts every workflow invariant WITH a negative control: T1 HAPPY+VAULT : a contract envelope with 2 ordered signers (+1 CC) sends, cannot complete before signing, completes once both have a verified seal, and the sealed version lands in the additive per-tenant vault. T2 NEVER-ROUTE-VOID (the s-class crux) : a Last Will & Testament in a NON-e-wills jurisdiction -> SEND is REFUSED_VOID and the envelope STAYS DRAFT. A generic e-sign clone would send it and collect a legally void signature; this one cannot. T3 ROUTING ORDER: signer 2 cannot sign before signer 1 (OUT_OF_ORDER), then in-order both sign and it completes. T4 TAMPER->NO-COMPLETE : a one-byte-tampered seal is rejected at SIGN (BAD_SEAL) so the envelope cannot complete; restoring the byte lets it sign + complete (forgery can't finish a deal). T5 DECLINE ADDITIVE : a decline makes the envelope terminal-DECLINED while the audit trail only GROWS and both recipients are retained (Rule 13 additive-only). T6 E-WILL NOT OVER-REFUSED : a properly executed e-will (testator + 2 witnesses + notary) in an e-wills state sends, signs and completes -- we refuse the VOID path, not the valid one. T7 TENANT ISOLATION : the per-tenant vault prefix discipline rejects '.'/'/'/empty tenant ids (no cross-tenant traversal). NOTE (honest): the gate uses the single RFC 8032 KAT keypair for determinism; binding each signer to their OWN key is a provisioning/PKI rung. What is proven here is the WORKFLOW logic + the legal invariants, not multi-key PKI. Evidence -> knowledge/status/doc_envelope.log license_tier: ORIGINAL