RenameFolderDialog — the id-model folder rename (only offered when the
user's folder migration is 'complete', they own the folder, and it is not
a system folder; the server independently enforces all three).
Client-side validation is deliberately light: a slash is refused here
because it can never mean anything but confusion, and everything else —
reserved names, collisions, system folders — is the server's call, whose
refusal text this dialog shows verbatim.
RenameFolderDialog — the id-model folder rename (only offered when the user's folder migration is 'complete', they own the folder, and it is not a system folder; the server independently enforces all three).
Client-side validation is deliberately light: a slash is refused here because it can never mean anything but confusion, and everything else — reserved names, collisions, system folders — is the server's call, whose refusal text this dialog shows verbatim.