1.60's own places that took a model file by name use the new helpers
too: the scan choice (model_file_within), the editor's covers, Tidy's
move (model_reference_within). Opening a folder keeps 1.60's "no file
name opens the folder". move_into tells a rename from a copy by where the
link is (lstat), so Tidy moving a linked model renames the link instead
of copying the model disk's file onto the server. The open-folder test
stubs through path_utils and also refuses "..".
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
