fix(empty-return-requests): show the queue to the staff who run returns

The menu item was gated on the brand-new empty_return_requests:view key,
which on the dev DB is held by one position (Operations Chief) — so the
Director and Dispatcher who already work Container Returns two rows above
it never saw the entry at all.

Viewing the queue now accepts that key OR warehouse_inventory:view, the
key the rest of the Imports menu runs on, in the sidebar, the route guard
and the API's read routes alike. Approving and rejecting stay on the
review key on their own, and the buttons come up disabled (with the
reason) for a viewer who lacks it rather than firing into a 403.

The dedicated keys are still there to hand out per position whenever
that call gets made.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/edr-freight-web/backoffice/src/pages/warehouses/EmptyReturnRequestsPage.tsx

@@ -18,6 +18,8 @@ import {
 } from "@mantine/core";
 import { DataTable, type ColumnDef } from "@edr/ui-common";
 
+import { useAuth } from "@/auth/useAuth";
+import { FREIGHT_PERMS, hasPermission } from "@/lib/permissions";
 import { PageContainer, PageHeader } from "@/components/page";
 import ListControls from "@/components/common/ListControls";
 import { extractErrorMessage } from "@/components/warehouses/options";