v0.46.2 — SLICE-0: §22.4a contract amendment (entry metadata is collection-configured, not type-driven)

Reframes binding SPEC.md §22.4a so a collection's entry metadata schema is
collection-configured — a `fields:` schema in `.collection.yaml` plus per-entry
`<slug>.meta.yaml` sidecars — rather than a frontmatter schema hard-wired to the
collection's `type`. Item 3's type-specific surfaces (release planning;
bdd scenario/coverage views) are deferred to a future design; bdd coverage is
recorded as a future `ref`-field surface rendered as hyperlinks (no cross-
collection corpus fusion). `type` still selects terminology (entry noun,
v0.45.0) + default initial_state/review posture (§22.4b-c).

SLICE-0 of docs/design/2026-06-06-configurable-collection-metadata.md (§7.2);
supersedes the per-type-surfaces draft (D11). Doc-only: per-type frontmatter
validation was never implemented, so no operator action, no schema/behavior
change. Sidecar storage + validation + UI arrive in SLICE-1+.

- SPEC.md §22.4a reframed; document/specification/bdd bullets updated; metadata
  amendment blockquote added.
- SPEC.md §2 and §22 forward-pointer blockquotes: "type-dependent frontmatter
  schema" -> "collection-configured, not type-driven (§22.4a, as amended)".
- CHANGELOG 0.46.2; VERSION + frontend/package.json -> 0.46.2.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.46.1",
+  "version": "0.46.2",
   "type": "module",
   "scripts": {
     "dev": "vite",