Enhancement: consider AVIF HDR support

Feature request

What are you trying to achieve?

Transform HDR AVIF images.

With both the AVIF format and HDR displays now being pretty much baseline, maybe it's time to start shipping prebuilt binaries that do support that?

When you searched for similar feature requests, what did you find that might be related?

I found an issue with a similar title, which was closed as "Completed" although Sharp still doesn't have HDR support.

What would you expect the API to look like?

No change in API, but using bitdepth: 10 in AvifOptions doesn't trigger an Expected 8 for bitdepth when using prebuilt binaries but received 10 of type number error. This means building libvips with HDR support.

What alternatives have you considered?

I think I have to look into trying to build binaries from source. Given I'm building my websites on the cloud (cloudflare pages) it's going to take some time to vendor the right binaries I guess.

Please provide sample image(s) that help explain this feature

https://github.com/AOMediaCodec/av1-avif/tree/master/testFiles/Netflix

Start by reviewing the repository's packaging scripts and how prebuilt libvips binaries are produced; the issue names no specific file or test. Determine how to build libvips with HDR support, then verify that bitdepth: 10 works with the linked Netflix AVIF samples without the current prebuilt-binary error.