feat(sdk-ts): add exchange-rates SDK functions

- Add fetchLatestExchangeRate function to retrieve exchange rates
- Add ExchangeRateLatestQuery and ExchangeRateLatestResponse types
- Export exchange-rates module from SDK index

shared/sdk-ts/src/exchange-rates.ts

@@ -0,0 +1,41 @@
+import type { ApiFetcher } from './fetch-utils';
+
+export const EXCHANGE_RATES_ROUTES = {
+  LATEST: '/api/exchange-rates/latest',
+} as const;
+
+/** Query params for GET /api/exchange-rates/latest */
+export interface ExchangeRateLatestQuery {
+  /** Source currency code (ISO 4217) */
+  from_currency?: string;
+  /** Target currency code (ISO 4217) */
+  to_currency?: string;
+}
+
+/** Response for GET /api/exchange-rates/latest */
+export interface ExchangeRateLatestResponse {
+  /** The base currency code */
+  baseCurrency: string;
+  /** The target currency code */
+  toCurrency: string;
+  /** The exchange rate value */
+  exchangeRate: number;
+}
+
+/**
+ * Fetches the latest exchange rate for the given currency pair.
+ * @param fetcher - The API fetcher instance
+ * @param query - Query parameters containing from_currency and/or to_currency
+ * @returns The exchange rate response with baseCurrency, toCurrency, and exchangeRate
+ */
+export async function fetchLatestExchangeRate(
+  fetcher: ApiFetcher,
+  query?: ExchangeRateLatestQuery,
+): Promise<ExchangeRateLatestResponse> {
+  const get = fetcher
+    .path(EXCHANGE_RATES_ROUTES.LATEST as never)
+    .method('get')
+    .create();
+  const { data } = await get((query ?? {}) as never);
+  return data as ExchangeRateLatestResponse;
+}

shared/sdk-ts/src/index.ts

@@ -14,6 +14,7 @@ export * from './bills';
 export * from './items';
 export * from './branches';
 export * from './warehouses';
+export * from './exchange-rates';
 export * from './expenses';
 export * from './import';
 export * from './manual-journals';