enterReorderMode method
Opens a drag-to-reorder session (P18): fetches the FULL, unpaginated
list ordered by the resource's declared reorder column
(source.list(reorder: true)), never the paginated rows already on
screen — a drag has to be able to place a record anywhere in the whole
set, not just within whichever page happened to be loaded. Sends the
list's current searchTerm along — a term already active on the
paginated list stays active once reorder mode opens, same as Filament.
A fetch failure surfaces on errorMessage and leaves isReordering false — the screen stays on its normal list rather than opening a reorder view with nothing in it.
Implementation
Future<void> enterReorderMode() => _fetchReorderedPage();