reorder abstract method
POST /{resource}/reorder — commits a full drag-to-reorder (P18), in the
records' new top-to-bottom order. ids are route keys
(ResourceRecord.id), first entry first — see
ResourceListProvider.saveReorder(), the only caller.
Unlike the writes above, there is no data-carrying failure outcome to
return — same contract as state/options — so a non-2xx throws
FilamentTransportException rather than degrading into a silent no-op.
Implementation
Future<void> reorder(String resourceKey, List<Object> ids);