[Bug] Reshare dialog offers Edit/Create/Delete from a read-only source, causing a "Cannot increase permissions" error

Steps to reproduce

1. As user A, share a folder with user B using Read + Share only (no edit/create/delete).
2. As user B, open the share dialog and reshare that folder (to a Team, or to another user).
3. In permissions, note that Edit is offered and enabled (the dialog starts at full permissions).
4. Leave Edit enabled and save.

Expected

User B can only reshare with the permissions they hold (read + share). Edit / Create / Delete should be disabled or hidden, since B can't grant them.

Actual

The share is rejected with Cannot increase permissions of <path>. B is offered a toggle they can't actually use and only learns that from a backend error.

Suggested fix

Clamp the default and selectable permissions to fileInfo.sharePermissions when resharing, so a read-only resharer can't pick edit/create/delete. Keep the backend guard as the safety net.

Start at the reshare dialog and trace how its permission controls and defaults use fileInfo.sharePermissions; then review the backend permission guard mentioned in the issue. Done means a user with only Read + Share cannot select Edit/Create/Delete when resharing, while the backend guard still rejects invalid permission increases.