fix: add ssh-keyscan for GitHub host key verification

.github/workflows/deploy.yml

@@ -84,6 +84,10 @@ jobs:
           key: ${{ secrets.SSH_PRIVATE_KEY }}
           port: ${{ secrets.SSH_PORT }}
           script: |
+            # Ensure GitHub host key is trusted (one-time setup).
+            mkdir -p ~/.ssh
+            ssh-keyscan github.com >> ~/.ssh/known_hosts 2>/dev/null
+
             PLUGIN_DIR="$HOME/domains/peptiderepo.com/public_html/wp-content/plugins/peptide-news-plugin"
             REPO_URL="git@github.com:peptiderepo/peptide-news-plugin.git"