Apply GH-DEC-2026-017 to the Taxonomy layer declaration and close RMASTER-WP-0027.

INTENT.md governs; layer.yaml is marked derived from it. standard_version is
removed from both. The value Taxonomy is unchanged: the ruling closes the
vocabulary at four tokens and Taxonomy is one of them. ADR-0010 amended by
revision (accepted-2). No checker in this repository reads the declaration.

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

docs/adr/ADR-0010-taxonomy-is-an-enumerated-layer.md

@@ -2,7 +2,7 @@
 id: RMASTER-ADR-0010
 title: "Taxonomy Is An Enumerated Layer, Not A Value Outside The Vocabulary"
 status: accepted
-revision: "accepted-1"
+revision: "accepted-2"
 owner: railiance-master
 last_reviewed: "2026-09-21"
 review_interval: 6m
@@ -150,3 +150,47 @@ is a decision that was taken, not an accident of a generator.
 
 Tracked in `RMASTER-WP-0027`. Sent to `gate-house` as input to the §3
 vocabulary ruling on 2026-09-21.
+
+## Revision accepted-2 (2026-09-21) — the ruling
+
+`gate-house` ruled in `GH-DEC-2026-017` (gate-house `decisions/decisions.md`;
+amendments A9, A11 and A12 in
+`gate-house/docs/amendments/v0.8-section-11-declaration-amendments.md`). The
+text above is left as accepted-1 recorded it; this section states what the
+ruling confirmed and what it changed.
+
+**Confirmed, unchanged:**
+
+- Decision 1 and 2. The §3 vocabulary is closed at **four** tokens —
+  `Taxonomy`, `Tooling`, `Engine`, `Staff` (§3 of the ruling, A9).
+  `layer: Taxonomy` is conforming and the validator carried the defect.
+  `flex-auth` has since fixed it (flex-auth `80ffe72`). The value is not
+  changed; the contingency in Decision 5 did not trigger.
+- Decision 3. `surface` was ruled apart from `Taxonomy`, as asked.
+- Scope. This repository is outside §4. The ruling (§4, A11) holds that §11
+  binds §4 repositories only, so our declaration is *declared voluntarily,
+  outside catalog scope*. It was never a §11 non-conformance, and is not one
+  now.
+
+**Changed by the ruling:**
+
+- **Precedence (Decision 4, question 1).** `INTENT.md` frontmatter governs.
+  `layer.yaml` is a derived artifact and now carries `derived: true` and
+  `derived_from: INTENT.md`. The two still agree.
+- **Case (Decision 4, question 2; the casing observation under Evidence).**
+  Comparison is ASCII case-insensitive and a lowercase declaration is
+  conforming, not tolerated. The Evidence observation that the nine
+  lower-casing sidecars "diverge from the standard's own spelling" is
+  superseded: under A9 they conform. Its underlying point — §3 writes
+  `Engines`, §4 writes `Engine` — became A9, which states the token once and
+  makes the §4 column spelling canonical. Our `Taxonomy` is canonical under
+  either reading.
+- **Standard version (Consequences, third bullet).** A layer declaration MUST
+  NOT carry a standard version (§5 of the ruling, A12). `standard_version: "0.7"`
+  is removed from `INTENT.md` frontmatter and `layer.yaml`, not re-pointed at
+  v0.8 as that bullet anticipated. Version-scoped state belongs in a derived
+  conformance record; this repository keeps none.
+
+This repository has no layer conformance checker of its own, so no checker or
+test had to change with the field. `RMASTER-WP-0027-T03` closes on this
+revision.