Fix rsync permission denied by specifying admin user

- Explicitly specify admin@HOST in rsync command
- Ensure proper user authentication for file transfer
- Fixes Permission denied error during rsync step

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

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

.github/workflows/deploy.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Rsync to NAS
         run: |
           rsync -avz -e "ssh -p ${{ secrets.NAS_PORT }}" ./ \
-            ${{ secrets.NAS_USER }}@${{ secrets.NAS_HOST }}:/volume1/homes/admin/nginx-infra/
+            admin@${{ secrets.NAS_HOST }}:/volume1/homes/admin/nginx-infra/
 
       - name: Remote docker-compose up
         run: |