fix(plugin-security): correct R1 door-order prose in object-posture-gate.ts

packages/plugins/plugin-security/src/object-posture-gate.ts

@@ -90,8 +90,21 @@ export function objectPostureGate(ctx: ObjectPostureGateContext): void {
 
  // R1 — ADR-0086 D1: an environment may only TIGHTEN a packaged object's
  // posture. Applies only to overlay writes over an artifact-backed object
- // (the OS_METADATA_WRITABLE escape-hatch path — the default deploy already
- // 403s these before this gate runs).
+ // (`ctx.isArtifactBacked`, the OS_METADATA_WRITABLE escape-hatch path).
+ // The answering layer is picked by the body's DIRECTION, not by deploy
+ // posture: a widening body meets R1 first on every leg — hatch open or
+ // closed, `?package=` named or not. On the host-config kernel the
+ // showcase boots, `saveMetaItem` runs `runAuthoringGate` ahead of the
+ // overlay/package doors (`environmentId` undefined, so protocol.ts's
+ // env-partitioned NOT_OVERRIDABLE branch never arms — see that file's own
+ // #7674 note). A non-widening body passes R1 and only then meets the
+ // overlay door: 403 NOT_OVERRIDABLE (no `?package=`) or 403 ITEM_LOCKED
+ // (`?package=` naming the read-only base) on stock, 200 under the escape
+ // hatch — WRITABLE_PACKAGE_REQUIRED appears on none of these paths.
+ // Measured on a stock showcase boot, six legs: #9477 (PR #9953, revision
+ // 3). Wire shape is `code: PERMISSION_DENIED` with `declaredCode:
+ // owd_widening_forbidden`, so a check keyed on `code` alone misses it
+ // (#9958).
  if (!ctx.isArtifactBacked) return;
  const declared = ctx.declaredBody as Record<string, unknown> | null;
  if (!declared || typeof declared !== 'object') return;