feat(freight-api): add DJF as a supported currency

Adds DJF to freight.payments_currency_enum (migration 3860000000000,
alone in its own migration per Postgres's ADD VALUE-in-a-transaction
restriction) and to manual_payment_settings (djf_enabled column,
migration 3870000000000, default true).

Replaces the binary ETB/USD assumptions that would have silently
mispriced or discarded a DJF booking:
- booking-pricing / contract-pricing: usdToEtb scalar -> a rate table
  keyed by source currency (ExchangeService.getRateTable), so a
  contract-frozen rate converts into whatever currency the booking is
  paid in instead of being dropped when neither leg is ETB or USD.
- warehouse-fee / booking-wagon-cancellation: normalizeCurrency no
  longer coerces anything non-ETB to USD.
- additional-charge: convertAmount no longer bails out for a currency
  that isn't literally ETB or USD.
- manual-payment-settings: isEnabled/enabledCurrencies cover DJF.

Widens the three @IsIn(['ETB','USD']) DTO validators, and adds DJF to
the export/report currency filter option lists.

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

apps/edr-freight-api/src/modules/exports/datasets/contracts.dataset.ts

@@ -112,6 +112,7 @@ export const contractsDataset: ExportDataset = {
     { key: 'paymentCurrency', label: 'Currency', type: 'select', options: [
       { value: 'ETB', label: 'ETB' },
       { value: 'USD', label: 'USD' },
+      { value: 'DJF', label: 'DJF' },
     ] },
     { key: 'serviceTypeId', label: 'Service type', type: 'text' },
     // Routes are one-to-many on contract_routes, so these filter via EXISTS

apps/edr-freight-api/src/modules/exports/datasets/invoices.dataset.ts

@@ -129,6 +129,7 @@ export const invoicesDataset: ExportDataset = {
     { key: 'currency', label: 'Currency', type: 'select', options: [
       { value: 'ETB', label: 'ETB' },
       { value: 'USD', label: 'USD' },
+      { value: 'DJF', label: 'DJF' },
     ] },
     { key: 'minAmount', label: 'Min total', type: 'text' },
     { key: 'maxAmount', label: 'Max total', type: 'text' },

apps/edr-freight-api/src/modules/exports/datasets/payments.dataset.ts

@@ -89,6 +89,7 @@ export const paymentsDataset: ExportDataset = {
     { key: 'currency', label: 'Currency', type: 'select', options: [
       { value: 'ETB', label: 'ETB' },
       { value: 'USD', label: 'USD' },
+      { value: 'DJF', label: 'DJF' },
     ] },
     { key: 'search', label: 'Search order or transaction ID', type: 'text' },
   ],