feat(lint): guard examples against bare metadata literals (#2035)

Adds an AST-only no-restricted-syntax rule that flags exported consts in
examples/** annotated with a spec domain type (simple `Page` or qualified
`UI.Page`) instead of being wrapped in the defineX factory. Turns the authoring
convention into an invariant so the "pick by history" pattern cannot creep back
into the reference corpus AI learns from — it already caught 15 unmigrated
authoring files in this change. No type info required.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: os-zhuang

eslint.config.mjs

@@ -31,6 +31,22 @@ const SUBPATH_RULE_MESSAGE =
   're-exports were removed because Node ESM cannot tree-shake them — see ' +
   'packages/spec/src/index.ts.';
 
+// issue #2035 — the 16 writable domains that now have a `defineX` factory. In
+// example/app metadata files these must be authored through the factory, never a
+// bare `: DomainType` / `: DomainTypeInput` literal: the factory validates at
+// `.parse()` time and is a *value* import that fails loudly on a broken import
+// instead of silently degrading to `any` (the #2023 failure mode).
+const DOMAIN_TYPES = [
+  'Datasource', 'Connector', 'Policy', 'SharingRule', 'Role', 'PermissionSet',
+  'EmailTemplateDefinition', 'Report', 'Webhook', 'ObjectExtension', 'Cube',
+  'Mapping', 'Theme', 'TranslationBundle', 'Page', 'Action',
+].flatMap((t) => [t, t + 'Input']).join('|');
+
+const DOMAIN_RULE_MESSAGE =
+  'Author this metadata through its defineX factory (e.g. `definePage({ ... })`) ' +
+  'instead of a bare `: Type` literal. The factory validates at parse time and a ' +
+  'broken value import fails loudly instead of degrading to `any` — see issue #2035.';
+
 export default [
   {
     files: ['**/*.{ts,tsx,mts,cts,js,jsx,mjs,cjs}'],
@@ -62,4 +78,29 @@ export default [
       }],
     },
   },
+  // issue #2035 — authoring-entry guard. Flags exported consts in example
+  // metadata files that are annotated with a spec domain type (simple `Page`
+  // or qualified `UI.Page`) instead of being wrapped in the `defineX` factory.
+  // AST-only (no type info): matches the declaration shape, not local vars or
+  // function params. Scoped to examples — the reference corpus AI learns from.
+  {
+    files: ['examples/**/*.{ts,tsx,mts,cts}'],
+    ignores: ['**/node_modules/**', '**/dist/**'],
+    languageOptions: {
+      parser: tsParser,
+      parserOptions: { ecmaVersion: 'latest', sourceType: 'module' },
+    },
+    rules: {
+      'no-restricted-syntax': ['error',
+        {
+          selector: `ExportNamedDeclaration VariableDeclarator[id.typeAnnotation.typeAnnotation.typeName.name=/^(${DOMAIN_TYPES})$/]`,
+          message: DOMAIN_RULE_MESSAGE,
+        },
+        {
+          selector: `ExportNamedDeclaration VariableDeclarator[id.typeAnnotation.typeAnnotation.typeName.right.name=/^(${DOMAIN_TYPES})$/]`,
+          message: DOMAIN_RULE_MESSAGE,
+        },
+      ],
+    },
+  },
 ];