🔧 fix: add GHCR authentication for staging server

The staging server needs to authenticate to ghcr.io to pull private images.
Added docker login step using GHCR_PAT secret before deployment.

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

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

.github/workflows/cd-staging-tagged.yml

@@ -306,6 +306,12 @@ jobs:
           # Copy the docker-compose file
           scp docker-compose.staging.yml ${{ secrets.STAGING_USER }}@${{ secrets.STAGING_HOST }}:~/manacore-staging/docker-compose.yml
 
+      - name: Login to GHCR on staging server
+        run: |
+          ssh ${{ secrets.STAGING_USER }}@${{ secrets.STAGING_HOST }} << EOF
+            echo "${{ secrets.GHCR_PAT }}" | docker login ghcr.io -u ${{ github.repository_owner }} --password-stdin
+          EOF
+
       - name: Deploy service
         env:
           VERSION: ${{ needs.parse-deployment.outputs.version }}