feat(import-operations): bulk Excel upload for yard-resident empty containers

Empties already sitting in an EDR yard but never entered in the system had
to be typed one at a time. Adds a bulk path: parse the sheet in the browser
(all-or-nothing, row-numbered errors), preview it, then POST one batch.

The server rejects the batch if any container already has a non-COMPLETED
return, so re-uploading the same sheet cannot duplicate boxes. No interchange
notification fires — these are historical rows, not a live handover.

Company is an Autocomplete over registered customers that also accepts a
typed name, since a backfilled box may belong to a company that is not a
customer yet. Exact name match sets customer_id; the name always lands in the
new empty_container_returns.company_name.

Also fixes the single Record Return modal, which collected Yard and Zone and
then dropped them before the API call, and did not invalidate the returns
list after a standalone return.

apps/edr-freight-web/backoffice/src/services/importOperations.service.ts

@@ -124,6 +124,17 @@ export const importOperationsService = {
     return unwrap(response.data);
   },
 
+  /** Backfill empties already in the yard. All-or-nothing on the server. */
+  bulkCreateEmptyReturns: async (
+    returns: CreateEmptyContainerReturnPayload[],
+  ): Promise<EmptyContainerReturn[]> => {
+    const response = await client.post<EmptyContainerReturn[]>(
+      URL_CONSTANTS.IMPORT_OPERATIONS.EMPTY_CONTAINER_RETURNS_BULK,
+      { returns },
+    );
+    return unwrap(response.data);
+  },
+
   loadEmptyContainersOnTrain: async (
     payload: LoadEmptyContainersOnTrainPayload,
   ): Promise<EmptyContainerReturn[]> => {