The cycle's design principle enters the ledger: every closed-vocabulary
entry the binary exposes carries a one-line meaning behind one shared
deterministic shape gate (doc_gate) at three seams -- compile/unit for
engine-shipped entries, load for native node crates, register for the
content-addressed store (documents: an additive-optional gated
description). Forbids the engine evaluating description text (C17 /
invariant 10), any influence on execution/identity/determinism (C1),
retroactive invalidation of registered artifacts, and machine-invented
meaning lines. Why: the audience is headless LLM agents (#319); field
evidence #314 showed schema knowledge being recovered by CAS forensics
from the release binary -- the removed failure class.
All spec acceptance criteria are now met across the four iterations of
this cycle (core carrier + std texts; domain threading; load seam;
register seam + op-script doc slot + document description).
closes#316
