Apply GH-DEC-2026-017: INTENT.md governs, the sidecar is derived, no version

- Remove standard_version from layer.yaml and INTENT.md frontmatter (§5, A12).
- Mark layer.yaml derived: true, derived_from: INTENT.md (§1, A11).
- Checker and tests change in the same commit: standard_version is no longer
  a required key (it is now rejected in either form), the derived marking is
  required, both layer values are checked against the closed four-token
  vocabulary, and the two forms are compared after an ASCII case fold (A9).
  A disagreement surviving the fold is reported as a finding.
- Nothing re-spelled: INTENT.md keeps "Engine", layer.yaml keeps "engine".

Scope check (§9.5 / GH-DEC-2026-017 §4): maturity-engine does not score
layer declarations anywhere. scoring.py grades gap-register conformance
states, and seed gaps concern capabilities, not §11 declarations, so no
non-§4 repository is graded. No scoring change required.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 63291@bnt-lap001
Assistant-Session: 8bd77868-ca68-4f49-bb1e-d539ecc0d703

INTENT.md

@@ -2,7 +2,6 @@
 layer: Engine
 role: PIP
 standard: netkingdom-security-layer-model
-standard_version: "0.7"
 companion: net-kingdom/SECURITY-COMPANION.md
 ---