Add train deactivation feature and import train number management

- Introduced DEACTIVATED status for trains, allowing staff to park trains indefinitely.
- Implemented methods to deactivate and reactivate trains in the TrainBuilderService.
- Added UI components for train deactivation and reactivation in TrainBuilderDetailPage.
- Created a dropdown setting for admin-managed import train numbers, with corresponding migrations.
- Updated yard code length to accommodate soft-delete suffix.
- Enhanced train status handling to include DEACTIVATED state.

apps/edr-freight-web/backoffice/src/hooks/useImportTrainNumberOptions.ts

@@ -0,0 +1,67 @@
+import { useQuery } from "@tanstack/react-query";
+import { useMemo } from "react";
+
+import { IMPORT_TRAIN_OPTIONS } from "@/constants/trainRuns";
+import { api } from "@/services/api";
+
+/** Dropdown-settings code holding the admin-managed IMPORT run numbers. */
+export const IMPORT_TRAIN_NUMBERS_CODE = "import_train_numbers";
+
+export interface ImportTrainNumberOption {
+  value: string;
+  label: string;
+  disabled?: boolean;
+}
+
+/**
+ * Selectable IMPORT run numbers for the Train Builder, sourced from the
+ * admin-managed `import_train_numbers` dropdown setting (admins add new runs
+ * from the Dropdown Settings editor). Falls back to the legacy hardcoded run
+ * list while the setting is missing or has no options.
+ *
+ * Numbers already claimed by an existing train are kept in the list but
+ * disabled and tagged "in use". Pass `currentNumber` when editing a train so
+ * its own number stays pickable, and so a legacy number that was removed from
+ * the setting still renders.
+ */
+export function useImportTrainNumberOptions(currentNumber?: string | null) {
+  const settingQuery = useQuery(
+    api.dropdownSettings.getByCode.queryOptions({
+      input: { code: IMPORT_TRAIN_NUMBERS_CODE },
+      staleTime: 5 * 60_000,
+      retry: false,
+    }),
+  );
+  const usedQuery = useQuery(
+    api.trainBuilder.usedTrainNumbers.queryOptions({ staleTime: 30_000 }),
+  );
+
+  const options = useMemo<ImportTrainNumberOption[]>(() => {
+    const configured = [...(settingQuery.data?.children ?? [])]
+      .filter((option) => !option.disabled)
+      .sort((a, b) => (a.order ?? 0) - (b.order ?? 0))
+      .map((option) => ({
+        value: option.value,
+        label: option.label || option.value,
+      }));
+    const base = configured.length ? configured : IMPORT_TRAIN_OPTIONS;
+
+    const used = new Set(usedQuery.data?.importTrainNumbers ?? []);
+    if (currentNumber) used.delete(currentNumber);
+
+    const items: ImportTrainNumberOption[] = base.map((option) =>
+      used.has(option.value)
+        ? { ...option, label: `${option.label} — in use`, disabled: true }
+        : option,
+    );
+    if (currentNumber && !items.some((option) => option.value === currentNumber)) {
+      items.unshift({ value: currentNumber, label: currentNumber });
+    }
+    return items;
+  }, [settingQuery.data, usedQuery.data, currentNumber]);
+
+  return {
+    options,
+    isLoading: settingQuery.isLoading || usedQuery.isLoading,
+  };
+}