feat(deed): (maturity …) repo-deed vocabulary

1-formats/deed/mappings/state-v1-decision.adoc

@@ -64,6 +64,11 @@ re-appearing.
   `(status … :maturity production)` — symbol, closed set as the comment
   taxon says. This is the single v1-vocabulary extension this family asks
   for, deliberately minimal and ruled-on-visible.
+  **Ruled 2026-10-02 (owner):** not the status field. Maturity is a clause
+  of its own, `(maturity :level … :since …)`, declared in
+  link:../vocabulary/maturity.adoc[vocabulary/maturity.adoc]. Option B's
+  translation therefore writes maturity there. Only this row is ruled; the
+  choice between A, B and C stays open.
 
 == 4. What is executable NOW without a ruling
 

1-formats/deed/tools/fixtures/valid/maturity-clause_chora.deed

@@ -0,0 +1,11 @@
+;; SPDX-License-Identifier: CC-BY-SA-4.0
+; Exercises every term of the (maturity ...) vocabulary:
+; 1-formats/deed/vocabulary/maturity.adoc
+(repo-deed
+  :schema-version "1.0.0"
+  :canonical-name "maturity-clause"
+  (status
+    :phase incubating)
+  (maturity
+    :level experimental
+    :since "2026-10-02"))

1-formats/deed/vocabulary/maturity.adoc

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: CC-BY-SA-4.0
+// SPDX-FileCopyrightText: 2026 Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+= `(maturity …)` — repo-deed vocabulary for maturity
+:toc:
+
+Status:: vocabulary, v1 (2026-10-02). Grammar unchanged: this is a `clause`
+under the normative link:../spec/abnf/deed.abnf[deed.abnf] v1.0.0.
+Ruling:: owner decision 2026-10-02: maturity is a clause of its own, not a
+`:maturity` field on the `status` clause. This settles the `maturity` row of
+link:../mappings/state-v1-decision.adoc[state-v1-decision] §3; the rest of
+that decision is still open.
+Fixture:: link:../tools/fixtures/valid/maturity-clause_chora.deed[maturity-clause_chora.deed].
+
+As with link:updates.adoc[`(updates …)`], no production `estate_chora.deed`
+exists yet, so this page is the declaration. The terms below move into that
+file's `(vocabulary …)` clause verbatim when it lands.
+
+== Why a clause of its own
+
+Phase and maturity answer different questions. Phase (the `status` clause's
+`:phase`) says where a repo is in its lifecycle: incubating, active,
+archived. Maturity says how far a consumer can rely on what it ships. A repo
+can be active and experimental, or archived and production. Keeping them in
+separate clauses means neither is read as a qualifier of the other.
+
+== Where it appears
+
+Only in a `repo-deed` (`<repo>_chora.deed`), at most once, as a direct child
+of the form. **No clause means the maturity is unstated**, not
+`experimental`: a reader must not invent a default.
+
+== Terms
+
+[cols="2,3,2,5",options="header"]
+|===
+| Term | Value | Required | Meaning
+
+| `:level` | SYMBOL, one of `experimental` `alpha` `beta` `production` `lts` | yes | How far a consumer can rely on the repo's output. The set is the one the v1 `[position] maturity` comment already named.
+| `:since` | STRING, `YYYY-MM-DD` | no | The date the repo reached this level.
+|===
+
+`experimental`:: Shape and behaviour may change without notice. Do not
+depend on it.
+`alpha`:: Usable for trials. Breaking changes are expected.
+`beta`:: Feature-complete for its stated scope. Breaking changes are
+announced.
+`production`:: Relied on by consumers. Breaking changes follow the repo's
+versioning policy.
+`lts`:: Production, with a stated support window.
+
+== Reader obligations
+
+* An unknown field inside `(maturity …)` is an error.
+* A `:level` outside the closed set is an error, never mapped to a nearby
+  value.
+* A string `:level` (`"beta"`) is an error: the value is a symbol.
+* A deed with two `(maturity …)` clauses is an error.
+
+== Example
+
+[source,lisp]
+----
+(maturity
+  :level experimental
+  :since "2026-10-02")
+----