Write out fsnative surface files registered to dhcpAsym/fsLR space

[tsalo]

A short summary of what you would like to see in NiBabies.

My understanding is that the resulting surface files will have the same vertices and mesh as the standard-space (dhcpAsym or fsLR) surface, but will retain the subject's fsnative geometry. This way users can visualize standard-space surface maps on the subject's unique topology (sulci, gyri, etc.), as is recommended in Jeganathan et al. (preprint).

Do you have any interest in helping implement the feature?

Yes!

Add any additional information or context about the request here.

This is something that XCP-D currently does with its "postprocess_surfaces_wf".