fix(qa): the dogfood package-first authoring assertion follows the rename

Sixth consumer found, and the one my local verification could not have caught:
the full-suite run I used as the safety net excludes @objectstack/dogfood by
design, so the dogfood shards were the one gate I had not actually run.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MaSQn77TT5fUgHK9CesaDK

Author: claude

packages/qa/dogfood/test/package-first-authoring.dogfood.test.ts

@@ -58,7 +58,7 @@ describe('dogfood: package-first authoring rejects runtime creates into read-onl
         packageId: codePkgId,
         mode: 'draft',
       }),
-    ).rejects.toMatchObject({ code: 'writable_package_required' });
+    ).rejects.toMatchObject({ code: 'WRITABLE_PACKAGE_REQUIRED' });
   });
 
   it('the same create into a fresh writable base id is NOT rejected (control)', async () => {