ci(lint): extend the authoring-entry guard to packages/apps (#2035) (#2097)

The #2088 guard only covered examples/**. Broadens it to the platform's own apps
(account/setup/studio) so the "author metadata via defineX, never a bare
`: DomainType` literal" convention holds across every authoring surface, not just
the example corpus. Explicitly excludes packages/downstream-contract, whose bare
literals are an intentional frozen backward-compat fixture (#2089).

No migrations — apps author no bare-literal metadata today; this is future-
proofing. Verified the guard fires on a probe under packages/apps and that
`pnpm lint` is green.

Co-authored-by: Jack Zhuang <277994282+os-zhuang@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

eslint.config.mjs

@@ -78,14 +78,16 @@ 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.
+  // issue #2035 — authoring-entry guard. Flags exported consts in 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 the authoring surfaces — the example corpus AI learns from and the
+  // platform's own apps. NOT downstream-contract: its bare literals are a frozen
+  // backward-compat fixture (#2089) and are intentional.
   {
-    files: ['examples/**/*.{ts,tsx,mts,cts}'],
-    ignores: ['**/node_modules/**', '**/dist/**'],
+    files: ['examples/**/*.{ts,tsx,mts,cts}', 'packages/apps/**/*.{ts,tsx,mts,cts}'],
+    ignores: ['**/node_modules/**', '**/dist/**', 'packages/downstream-contract/**'],
     languageOptions: {
       parser: tsParser,
       parserOptions: { ecmaVersion: 'latest', sourceType: 'module' },