fix(ci): disable checkout persist-credentials for cross-repo auth

The default GITHUB_TOKEN extraheader was overriding the PAT-based
git URL rewrite, causing private dep access to fail.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jt55401

.github/workflows/ci.yml

@@ -12,6 +12,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
 
       - uses: actions/setup-node@v4
         with: