`env-test-guard` was removed from crates.io for malicious code

`env-test-guard` attempted to exfiltrate credentials from the environment to an
arbitrary URL.

The malicious crate had 2 versions published on 2026-03-24 and 2026-03-25,
approximately 8 months before removal, and had no evidence of actual usage.
This crate had no dependencies on crates.io.

Thanks to [Bitbison](https://bitbison.io/) for the report.