Methods used:
- published VM101 Machine Git baseline as source of target code;
- exact source hash gate on VM101;
- existing nested SSH route from XS Map;
- existing runtime helper library;
- raw stdin, same-directory temporary file and atomic mv;
- existing Machine Git v2 and router-machine-close.

Environment limitations:
- no full downloader execution;
- no refresh or rebalance;
- no VM100 or VM121 inspection/change;
- no service restart;
- no new SSH keys, aliases, libraries or recovery mechanisms.