fix: normalize escaped SSH private key secrets

.gitea/workflows/kubeadm-reset.yml

@@ -42,7 +42,7 @@ jobs:
             exit 1
           fi
 
-          printf '%s\n' "$KEY_CONTENT" | tr -d '\r' > ~/.ssh/id_ed25519
+          KEY_CONTENT="$KEY_CONTENT" python3 -c 'import os, pathlib; key=os.environ.get("KEY_CONTENT", "").replace("\r", ""); key=key.replace("\\n", "\n") if "\\n" in key and "\n" not in key else key; pathlib.Path.home().joinpath(".ssh", "id_ed25519").write_text(key if key.endswith("\n") else key + "\n")'
           chmod 0600 ~/.ssh/id_ed25519
 
       - name: Set up Terraform