Changes:
- NoteEditorViewModel.sortChecklistItems(): Use _lastChecklistSortOption.value instead of always sorting unchecked-first
- Supports all sort modes: MANUAL, UNCHECKED_FIRST, CHECKED_FIRST, ALPHABETICAL_ASC/DESC
- reloadFromStorage() also benefits from fix (uses same sortChecklistItems method)
- Root cause: loadNote() correctly restored _lastChecklistSortOption but sortChecklistItems() ignored it
7dbc06d102