Add SSH key setup step to deployment workflow

.github/workflows/deploy.yml

@@ -25,6 +25,13 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Setup SSH key
+        run: |
+          mkdir -p ~/.ssh
+          echo "${{ secrets.SSH_PRIVATE_KEY }}" > ~/.ssh/id_rsa
+          chmod 600 ~/.ssh/id_rsa
+          ssh-keyscan -p "${{ secrets.SSH_PORT }}" "${{ secrets.SSH_HOST }}" >> ~/.ssh/known_hosts
+
       - name: Deploy (pull, up, prune)
         run: |
           ssh -p "${{ secrets.SSH_PORT }}" "${{ secrets.SSH_USER }}@${{ secrets.SSH_HOST }}" \