feat(POS-FIX-6): completed feature

project/apps/pos/src/lib/api-client.ts

@@ -3,11 +3,12 @@
 const API = '/api';
 
 async function apiFetch<T>(path: string, init?: RequestInit): Promise<T> {
+  const hasBody = init?.body !== undefined && init.body !== null && init.body !== '';
   const res = await fetch(`${API}${path}`, {
     ...init,
     credentials: 'include',
     headers: {
-      'Content-Type': 'application/json',
+      ...(hasBody ? { 'Content-Type': 'application/json' } : {}),
       ...(init?.headers ?? {}),
     },
   });
@@ -102,6 +103,12 @@ export const posApi = {
       method: 'POST',
       body: JSON.stringify({ email }),
     }),
+  /** Print receipt for any sale (pending, completed, refunded). */
+  printReceipt: (orderId: string) =>
+    apiFetch<{ url: string }>(`/pos/sales/${encodeURIComponent(orderId)}/print`),
+  /** Get full receipt for a sale (used for returns). */
+  getReceipt: <T>(orderId: string) =>
+    apiFetch<T>(`/pos/sales/${encodeURIComponent(orderId)}/receipt`),
 };
 
 export const authApi = {