feat(train-scheduling): auto-place intercity cargo on wagons freed mid-corridor

Intercity bookings ride the wagons freed by earlier unloads (e.g. import
containers uncoupled at Dire Dawa). loadBooking now auto-allocates a
DOMESTIC booking onto on-train slots whose cargo has all departed —
greedy in consist order by capacity, container numbers copied for the
marshalling tally. Falls back to unallocated load when nothing is free.

apps/edr-freight-web/backoffice/src/pages/trainScheduling/TrainScheduleTrackPage.tsx

@@ -5,6 +5,7 @@ import {
   ArrowLeft,
   CalendarClock,
   CheckCircle2,
+  FileText,
   Flag,
   MapPin,
   Navigation,
@@ -40,6 +41,8 @@ import { freightBrand } from "@/theme/freight-brand";
 import { useMutation, useQuery } from "@tanstack/react-query";
 import { api } from "@/services/api";
 import { useToast } from "@/hooks/use-toast";
+import { openPdfBlob } from "@/components/warehouses/pdf";
+import { trainSchedulingService } from "@/services/trainScheduling.service";
 
 const parseError = (error: unknown, fallback: string) => {
   if (isAxiosError(error)) {
@@ -160,6 +163,31 @@ export default function TrainScheduleTrackPage() {
       enabled: Boolean(scheduleId) && trackQuery.data?.status === "DISPATCHED",
     }),
   );
+  // Marshalling 2: the current on-board list, reprinted after station work.
+  const intercityMarshalling = useMutation({
+    mutationFn: () =>
+      trainSchedulingService.downloadIntercityMarshallingDocument(scheduleId ?? ""),
+  });
+  const openIntercityMarshalling = async () => {
+    const pdfWindow = window.open("", "_blank");
+    try {
+      const blob = await intercityMarshalling.mutateAsync();
+      const opened = openPdfBlob(blob, `intercity-marshalling-${scheduleId}.pdf`, pdfWindow);
+      toast({
+        title: "Intercity marshalling ready",
+        description: opened
+          ? "The PDF opened in a browser tab for printing or saving."
+          : "The browser blocked the preview tab, so the PDF was downloaded.",
+      });
+    } catch (error) {
+      pdfWindow?.close();
+      toast({
+        title: "Could not open intercity marshalling document",
+        description: parseError(error, "Please try again"),
+        variant: "destructive",
+      });
+    }
+  };
   const [yardModal, setYardModal] = useState<{
     station: TrackStation;
     isFinal: boolean;
@@ -249,17 +277,32 @@ export default function TrainScheduleTrackPage() {
 
   return (
     <PageContainer>
-      <Button
-        component={Link}
-        to={`/dashboard/operations/train-scheduling-v2/${scheduleId}`}
-        variant="subtle"
-        color="gray"
-        size="compact-sm"
-        leftSection={<ArrowLeft size={16} />}
-        w="fit-content"
-      >
-        Back to schedule
-      </Button>
+      <Group justify="space-between" w="100%">
+        <Button
+          component={Link}
+          to={`/dashboard/operations/train-scheduling-v2/${scheduleId}`}
+          variant="subtle"
+          color="gray"
+          size="compact-sm"
+          leftSection={<ArrowLeft size={16} />}
+          w="fit-content"
+        >
+          Back to schedule
+        </Button>
+        {inTransit || arrived ? (
+          <Button
+            variant="light"
+            color="edr-green"
+            radius="lg"
+            size="compact-sm"
+            leftSection={<FileText size={16} />}
+            loading={intercityMarshalling.isPending}
+            onClick={() => void openIntercityMarshalling()}
+          >
+            Intercity Marshalling
+          </Button>
+        ) : null}
+      </Group>
 
       {/* ── Hero: gradient wash, route + a bold progress ring woven together ── */}
       <Paper