- Use _sanitize_subprocess_env() to filter Hermes-managed credentials
from the cua-driver subprocess environment (issue #37878)
- Prevents credential exfiltration to the third-party cua-driver binary
- Aligns with existing pattern used by browser-tool and other tools
- Add regression test to verify environment sanitization
The cua-driver is a lower-trust MCP subprocess per SECURITY.md §2.3.
Its inherited environment is now scrubbed by default, removing provider
API keys, gateway tokens, and platform credentials that should not leak
to third-party binaries.
Fixes#37878
2e5c04aaf7