chore: Use pure OIDC for npm publishing (no registry-url)

Remove registry-url from setup-node to let npm use OIDC trusted publishing
directly without the .npmrc interference.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/release.yml

@@ -83,7 +83,6 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '20'
-          registry-url: 'https://registry.npmjs.org'
 
       - name: Publish to npm
         run: |