Install OpenSSH client in deploy workflow

.gitea/workflows/redeploy-compose.yml

@@ -16,6 +16,22 @@ jobs:
       DEPLOY_BRANCH: main
       SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
     steps:
+      - name: Install SSH client tools
+        shell: bash
+        run: |
+          set -euo pipefail
+          if command -v apk >/dev/null 2>&1; then
+            apk add --no-cache openssh-client
+          elif command -v apt-get >/dev/null 2>&1; then
+            apt-get update
+            apt-get install -y --no-install-recommends openssh-client
+          elif command -v dnf >/dev/null 2>&1; then
+            dnf install -y openssh-clients
+          else
+            echo "No supported package manager found to install ssh-keyscan."
+            exit 1
+          fi
+
       - name: Validate required secrets
         shell: bash
         run: |