fix: Repair deploy workflow YAML (indent heredoc)

.gitea/workflows/deploy.yml

@@ -108,9 +108,9 @@ lines = []
           for k, v in env.items():
               if v is None:
                   continue
-    lines.append(f"{k}={v}")
+              lines.append(f\"{k}={v}\")
 
-Path("backend.env").write_text("\n".join(lines) + "\n")
+          Path(\"backend.env\").write_text(\"\\n\".join(lines) + \"\\n\")
 PY
 
       - name: Upload backend env to server