[ThinkAuth](https://auth.sys.thinkhead.org/) to 2025.8.1 to [mitigate Bitnamigate](https://docs.thin

Tracking ticket for a line in release 5.1.16.7 that shipped without one.

Upgraded ThinkAuth to 2025.8.1 to mitigate Bitnamigate [50].

Created retroactively so every changelog line has a ticket a reader can follow.