fix(spec): keep liveness gate + api-surface green for the view union schema

Two CI gates broke on the #3095 change that maps `view` to a union:

- Spec property liveness: `check-liveness.mts` walked each metadata type's
  top-level OBJECT shape; a union has none, so it threw "view is not an object
  schema". Teach `shapeOf` to resolve a union to its first object-typed member
  — the canonical authorable container (list/form/listViews/formViews) the
  ledger governs. Discriminated-union members (ViewItem) are skipped; their
  inner config is the same ListView/FormView surface already governed under the
  container's list/form children.
- API-surface snapshot: record the two intended new public exports
  (`ViewMetadata` type, `ViewMetadataSchema` const) via gen:api-surface.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LFmMsWLC3CVULh3Ke7rUdd

Author: claude

packages/spec/api-surface.json

@@ -3471,6 +3471,8 @@
     "ViewKeyCollision (interface)",
     "ViewKind (type)",
     "ViewKindSchema (const)",
+    "ViewMetadata (type)",
+    "ViewMetadataSchema (const)",
     "ViewSchema (const)",
     "ViewScope (type)",
     "ViewScopeSchema (const)",

packages/spec/scripts/liveness/check-liveness.mts

@@ -87,8 +87,22 @@ function unwrap(s: any, depth = 0): any {
 function shapeOf(s: any): Record<string, any> | null {
   const u = unwrap(s);
   const def = defOf(u);
-  if (def?.type !== 'object') return null;
-  return def.shape ?? u.shape ?? null;
+  if (def?.type === 'object') return def.shape ?? u.shape ?? null;
+  // #3095 — a metadata type may register a UNION of shapes rather than a single
+  // object (e.g. `view`: defineView container | ViewItem record | flattened
+  // personalization overlay). The liveness ledger governs the canonical
+  // authorable **container**, which is the first object-typed member of the
+  // union. Discriminated-union members (ViewItem) are skipped — their inner
+  // `config` is the same ListView/FormView surface already governed under the
+  // container's `list` / `form` children — so this walks the container shape.
+  if (def?.type === 'union' && Array.isArray(def.options)) {
+    for (const opt of def.options) {
+      const uo = unwrap(opt);
+      const od = defOf(uo);
+      if (od?.type === 'object') return od.shape ?? uo.shape ?? null;
+    }
+  }
+  return null;
 }
 function descOf(s: any): string {
   let cur = s;