Fix GHCR permission issues: add top-level permissions and use repository_owner

- Add top-level permissions block with contents: read and packages: write
- Change GHCR login username from github.actor to github.repository_owner
- Addresses permission_denied: write_package error from job ref fd0df22

Co-authored-by: leonpwd <60449031+leonpwd@users.noreply.github.com>

Author: Copilot

.github/workflows/build-and-push.yml

@@ -1,5 +1,10 @@
 name: Build and Push Docker Image
 
+# Top-level permissions: explicitly request package write rights for GITHUB_TOKEN
+permissions:
+  contents: read
+  packages: write
+
 on:
   push:
     branches:
@@ -27,7 +32,7 @@ jobs:
         uses: docker/login-action@v3
         with:
           registry: ghcr.io
-          username: ${{ github.actor }}
+          username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push Docker image