emulators/supermodel: Update 0.3a-20260506 => 0.3a-20260726

While here:

• Use tab instead of space in DISTVERSIONSUFFIX (pet portlint).
• Use UCL format in pkg-message.
• Fix sanity check by setting GH_PROJECT.

Commit log:
https://github.com/trzy/Supermodel/compare/v0.3a-20260506-git-9c9e7b7...v0.3a-20260726-git-b7d8acd

PR: 297178
Reported by: Hywel Andrews <owlandrews@protonmail.com> (maintainer)
Approved by: osa, vvd (Mentors, implicit)