Zenos yae Galvus: Echo 1

Fixes a recurrence of [CVE-2025-24369](https://github.com/Xe/x/security/advisories/GHSA-56w8-8ppj-2p4f)
due to an incorrect logic change in a refactor. This allows an attacker to mint a valid
access token by passing any SHA-256 hash instead of one that matches the proof-of-work
test.

This case has been added as a regression test. It was not when CVE-2025-24369 was released
due to the project not having the maturity required to enable this kind of regression testing.
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