nx_doc_annotate_gate.nx

nx_doc_annotate_gate.nx -- GATE for LEGAL D4 (nx_doc_annotate). Drives the annotation/markup overlay composing D1 (vault versions) + D2 (envelope completion -> the freeze) + D5 (real Ed25519 seal to complete it) and asserts every overlay invariant WITH a negative control: T1 ADD + COUNT + TYPE : notes/comments/highlights/redlines/checks/sigfields land on a doc version; per-type counts are exact. T2 REDLINE LIFECYCLE : a redline accepts (resolver recorded); another rejects and is RETAINED (additive, count unchanged). T3 THREADED COMMENTS : a comment + 2 replies -> thread_replies = 2. T4 CHECKLIST GATES SEND : 3 required checklist items, 2 done -> complete=0 (a portal withholds nx_env_send); all done -> complete=1 and nx_env_send = OK (compose w/ D2). T5 IMMUTABLE-AFTER-COMPLETE (the crux) : (a) frozen=1 -> add/resolve REFUSED; (b) a REAL envelope driven to COMPLETED yields frozen := (status==COMPLETED) and a subsequent add is REFUSED; control: a still-SENT envelope frozen=0 -> add succeeds. A signed agreement can't be re-marked. T6 PER-VERSION ANCHORING : an annotation on v1 is not counted for v2 after a vault version bump (it stays pinned to v1). T7 HISTORY READABLE UNDER FREEZE : a completed doc's prior annotations remain fully readable + counted; only NEW writes are refused. NOTE (honest): uses the single RFC 8032 KAT keypair for determinism (per-signer keys = a PKI rung). What is proven is the overlay lifecycle + the freeze/additive invariants and their composition with the real envelope + vault. Evidence -> knowledge/status/doc_annotate.log license_tier: ORIGINAL