Shortcut labels follow the OS egui reports ("Ctrl+B" against "⌘B"), so
the snapshots were only host-independent because kittest happens to
default to Nix. Pin it explicitly. With the OS set to Mac the test fails
on the Bookmarks panel's "New bookmark (⌘B)" button.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>