Multi Loader nodes previously sized their output sockets to the loaded
file count, so deleting one file shrank the sockets and destroyed any
wire on a later socket. Add an output_slots combo (auto/1-8, front-end
only — Python already returns a fully padded output list) so a fixed
socket count can be pinned and wires survive file-list edits; the
status line now flags file/socket-count mismatches.
Also drop the separate + Add button: the drop zone itself is now
clickable and opens the same file picker, so there is one field for
both drag-and-drop and click-to-browse.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
