feat(train-scheduling): numbered marshalling-doc picker per corridor stop

Backend now generates a separate marshalling document per corridor stop
where the consist actually coupled/uncoupled/switched something
(marshallingStops/marshallingDocumentAt), instead of one 'current
position' doc. Wires that into the backoffice:

- TrainScheduleV2DetailPage: the single Intercity Marshalling menu item
  becomes one item per stop with a logged change, falling back to the
  old single item when nothing has happened yet.
- TrainScheduleTrackPage: same fallback/menu treatment on its own
  marshalling button.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/edr-freight-web/backoffice/src/constants/QUERY_KEYS.ts

@@ -161,6 +161,8 @@ export const QUERY_KEYS = {
       ["train-scheduling", "schedules", filters ?? {}] as const,
     scheduleById: (id: string) => ["train-scheduling", "schedule", id] as const,
     track: (id: string) => ["train-scheduling", "track", id] as const,
+    marshallingStops: (id: string) =>
+      ["train-scheduling", "marshalling-stops", id] as const,
     batchBoard: (filters?: unknown) =>
       ["train-scheduling", "batch-board", "list", filters ?? {}] as const,
     batchBoardDetail: (scheduleId: string) =>

apps/edr-freight-web/backoffice/src/constants/URLS.ts

@@ -537,6 +537,10 @@ export const URL_CONSTANTS = {
       `/train-scheduling/schedules/${id}/export/load-list/document`,
     INTERCITY_MARSHALLING_DOCUMENT: (id: string) =>
       `/train-scheduling/schedules/${id}/intercity/marshalling/document`,
+    MARSHALLING_STOPS: (id: string) =>
+      `/train-scheduling/schedules/${id}/marshalling/stops`,
+    MARSHALLING_DOCUMENT_AT: (id: string, stopIndex: number) =>
+      `/train-scheduling/schedules/${id}/marshalling/document/${stopIndex}`,
     CHECKPOINTS: (id: string) =>
       `/train-scheduling/schedules/${id}/checkpoints`,
     CHECKPOINT: (id: string, sequenceNo: number) =>