references to files in /tmp in error messages are uhelpful

[errordeveloper]

Due to that modules are copied to a temporary directory, errors like this can occur:

✗ open /var/folders/gm/dnc405js6nlb275l4v2gh_b40000gn/T/timoni1961184784/module/cue.mod/module.cue: no such file or directory

This is a little disorienting to the users because files get deleted right away. If copying cannot be avoided, perhaps some other UX measures can be taken, e.g. check cue.mod/module.cue up front.