Add freight demo data seeder and permissions management

- Introduced `DemoFreightDataSeeder` to seed demo freight data including wagons, approval rules, and staff users.
- Added `seed:freight-demo` script to `package.json` for easy execution.
- Updated permissions for operations officer and added permission checks in various components.
- Enhanced sidebar and booking actions to respect user permissions.

apps/edr-freight-web/backoffice/src/lib/permissions.ts

@@ -16,6 +16,10 @@ export const FREIGHT_PERMS = {
     operations: "edr_freight_app:bookings:operations",
     cancel: "edr_freight_app:bookings:cancel",
   },
+  trainScheduling: {
+    view: "edr_freight_app:train_scheduling:view",
+    manage: "edr_freight_app:train_scheduling:manage",
+  },
 } as const;
 
 const slugToResourceKey = (slug: RuleEngineResourceSlug): string =>
@@ -70,6 +74,14 @@ export function canAccessBookings(user: AuthUser | null | undefined): boolean {
   return hasPermission(user, FREIGHT_PERMS.bookings.view);
 }
 
+export function canViewScheduling(user: AuthUser | null | undefined): boolean {
+  return hasPermission(user, FREIGHT_PERMS.trainScheduling.view);
+}
+
+export function canManageScheduling(user: AuthUser | null | undefined): boolean {
+  return hasPermission(user, FREIGHT_PERMS.trainScheduling.manage);
+}
+
 export function ruleEngineViewKey(slug: RuleEngineResourceSlug): string {
   return `edr_freight_app:rule_engine:${slugToResourceKey(slug)}:view`;
 }