Add three CERN licenses

[MikeCoats]

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Summary

This adds three new licenses. It includes the CERN Open Hardware Licence Version 2 - Permissive, Strongly Reciprocal and Weakly Reciprocal variants, known by the CERN-OHL-P-2.0, CERN-OHL-S-2.0 and CERN-OHL-W-2.0 SPDX identifiers respectively.

Linked issues

I copied the approach taken in #4389. Let me know if you've another preferred way you'd like to handle this instead.

Description of changes

• Adds three licenses to the ModelsHelper > license_select_options method.
• Adds three "translations" to the English locale.
• Adds a test to ensure one of our new options is visible in the licence drop down.

[Floppy]

Thanks!

[MikeCoats]

I've had a look at the failing check, @Floppy, but I'm not sure it's something I can fix?

It looks like it's failing to upload the code coverage stats because I'm missing the project token. I assume this is because the token's a Github Secret, so it isn't shared with external forks.

https://github.com/manyfold3d/manyfold/actions/runs/16921248778/workflow?pr=4633#L31

Let me know if there's something you need me to do to free it up from my side.

[Floppy]

Ah, no worries, that's normal for builds from forks (though I do need to fix it). The tests are passing, so I'll merge manually. Thanks!