cuelang.org: verify that content works with cmd/cue binaries from releases

[myitcv]

What page were you looking at?

https://cuelang.org/docs/howto/generate-cue-from-local-go/

What version of the site were you looking at?

https://github.com/cue-lang/cuelang.org/commit/eaf435881108b2cd01d7ef072e61400f783507ca

What did you do?

Followed the guide on the page, using v0.12.0

What did you expect?

To be able to run the example

What did you see instead?

could not load Go packages:
        an.example: -: This application uses version go1.23 of the source-processing packages but runs version go1.24 of 'go list'. It may fail to process source files that rely on newer language features. If so, rebuild the application using a newer version of Go.

[myitcv]

There are two things we need to fix here:

1. do a backport release of CUE using go1.24.x - cc @mvdan
2. fix cuelang.org build/testing processes to use the official binaries where available - @myitcv

[mvdan]

For point 2 above, it's important to note that the guide's go mod init command has to be run with the latest Go version for the go/packages error above to reproduce if cmd/cue was built with an older Go version. Paul confirms that the website already builds with the latest Go version by design, so that should be covered, but I wanted to make that note here.

[mvdan]

The backport release happened here: https://github.com/cue-lang/cue/releases/tag/v0.12.1

I've retitled the issue to be about the cuelang.org sanity checking that Paul mentions above.