feat(freight-backoffice): support DJF in booking, contract and warehouse screens

Currency dropdowns/pickers (AdditionalPaymentsTab, ClearanceChargesTab,
PhasedClearanceActionPanel, AdviseDutyCard, ContractRequestsPage,
ruleEngine/resources, WarehouseRulesPage, VehicleDetailPage,
FeePreviewModal) offer DJF alongside ETB/USD; GlCreateBookingForm's
currency selector gets allowDjf next to allowUsd. Narrow 'ETB'|'USD'
type unions widened to include 'DJF' across the warehouse
billingCurrency plumbing (useWarehouses, warehouse.service, api.ts)
and the customer/invoice types.

Ad-hoc money() formatters (BookingTrucksPanel, AccrualDashboard,
ImportTrucksPage, EmptyReturnRequestsPage) and formatMoney call sites
that hardcoded 2 decimals (wagon-cancellation cards, BookingRequestDetailPage,
WagonCancellationsPage, PaymentsPage, WarehouseInvoicesPage) now use
currencyDecimals() from @edr/ui-common so DJF renders with 0 decimals
instead of forced cents. The 3 duplicate overview formatCurrency/
formatAmount helpers (typed 'ETB'|'USD') widen to accept any currency.

Two correctness fixes: OverviewRecentBookingsTable's currency==='USD'
? 'USD' : 'ETB' was mislabeling every non-USD currency as ETB; and
WarehouseInvoicesPage's gateway-method default now routes any
non-ETB currency (not just USD) to WAAFI, so DJF invoices get a
working default instead of TELEBIRR (ETB-only).

Claude-Session: https://claude.ai/code/session_01CZy77vCWhka3pnmVF9NDkL

apps/edr-freight-web/backoffice/src/components/overview/OverviewRecentBookingsTable.tsx

@@ -9,10 +9,9 @@ import { SummaryCard } from "./summary/SummaryCard";
 
 function formatAmount(amount: number | null, currency: string | null) {
   if (amount == null) return "—";
-  const code = currency === "USD" ? "USD" : "ETB";
   return new Intl.NumberFormat("en-US", {
     style: "currency",
-    currency: code,
+    currency: currency || "ETB",
     maximumFractionDigits: 0,
   }).format(amount);
 }