docs(1.0): C4 metamodelVersion — capture agreed design (rolled-up, manifest-tagged)

One rolled-up spec-version string (a named freeze of the core provider set, tagging the
existing expected-registry.json manifest) exposed per registry + conformance-asserted —
NOT per-provider, NOT a per-file yaml/json stamp, core vocabulary only (downstream
providers outside the promise). Distribution-version pattern (OTel/protobuf-editions).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GF9xLEQZaPus5Y6opk398n

Author: claude

docs/1.0-readiness.md

@@ -63,11 +63,28 @@ Status legend: ✅ done · 🔶 in progress · ⬜ not started · ❓ **[RATIFY]
   program + the ADR-0039 own-accessor fix) and `0.14.0`/`7.6.0` (verify strict-default,
   jsonb parsed-value). `index.*` **reset the quiet-period clock** — the first
   no-breaking coordinated release must come *after* `0.15.1`/`7.7.1` (see G3).
-- ⬜ **C4. Add the `metamodelVersion` marker** (A1 dependency). A machine-readable
-  spec-version field the loader/registry exposes and every port emits, asserted by the
-  conformance matrix — the artifact that lets packages version independently while all
-  claiming "implements Metamodel 1.0." Pre-cut the vocabulary is "Metamodel 0.x"; the
-  cut freezes it as `1.0`.
+- ⬜ **C4. Add the `metamodelVersion` marker** (A1 dependency). A single **rolled-up**
+  spec-version string the loader/**registry** exposes and every port emits, asserted by
+  the conformance matrix — the artifact that lets packages version independently while
+  all claiming "implements Metamodel 1.0." Pre-cut the vocabulary is "Metamodel 0.x";
+  the cut freezes it as `1.0`. **Design (agreed 2026-07-02):**
+  - **One rolled-up number, not per-provider.** `Metamodel 1.0` is a *named freeze* of
+    the core provider set (distribution-version pattern, à la OTel spec releases /
+    protobuf editions). It is a **version tag on the existing
+    `fixtures/registry-conformance/expected-registry.json` manifest** — which is already
+    the byte-exact bill of materials every port is gated against — not a new
+    per-provider versioning system. Per-provider precision lives in that manifest,
+    machine-checked, never human-tracked.
+  - **Registry/runtime property, NOT a per-file stamp.** It does not go in the YAML/JSON
+    metadata documents (validity is decided by the loader's registered providers, so
+    there is no yaml/json duplication to manage). *(An optional per-file "targets
+    Metamodel X.Y" is separable and YAGNI for 1.0.)*
+  - **Core vocabulary only.** Downstream-added providers are outside the promise
+    (ADR-0023) and do not change this number; an app may version its own providers if it
+    cares — the library's concern is the core set.
+  - Scope: pick the exposure API per port (e.g. `registry.metamodelVersion`), stamp the
+    manifest, assert byte-equality of the string across all five ports in
+    `registry-conformance`.
 - ⬜ **C5. Adopt the minor-vs-patch cadence rule** (ADR-0035 §3, going forward). Trigger
   is *new public surface, not code size*: package **MINOR** only for newly-dependable
   surface (codegen output, CLI flag, a newly-supported vocab member); package **PATCH**