added product import and billing integration

lib/data/repositories/sync_repository_impl.dart

@@ -437,12 +437,12 @@ class SyncRepositoryImpl implements SyncRepository {
         'registered_by_terminal': _store.terminal.code,
       };
 
-  /// The JSON body sent per order.
+  /// The JSON body sent per order. Matches the back office's `/orders`
+  /// schema field for field — nothing added beyond it.
   Map<String, Object?> _orderToPayload(SaleTransaction t) => {
         'id': t.id,
         'invoice_number': t.invoiceNumber,
         'created_at': t.createdAt.toIso8601String(),
-        'terminal_id': t.terminalId,
         'cashier': t.cashierName,
         'customer': t.customer == null
             ? null
@@ -453,15 +453,6 @@ class SyncRepositoryImpl implements SyncRepository {
               },
         'subtotal': t.cart.subtotal,
         'discount': t.cart.billDiscountTotal + t.cart.lineDiscountTotal,
-        'promos': [
-          for (final applied in t.cart.appliedPromos)
-            {
-              'id': applied.promo.id,
-              'name': applied.promo.name,
-              'type': applied.promo.type.name,
-              'amount': applied.amount,
-            },
-        ],
         'tax': t.cart.taxAmount,
         // GST per slab, as printed on the invoice. Sent as well as the total
         // because a compliant tax return is filed per slab, and recomputing the

lib/data/repositories/transaction_repository_impl.dart

@@ -30,6 +30,35 @@ class TransactionRepositoryImpl implements TransactionRepository {
     await _store.refreshUnsyncedCount();
   }
 
+  @override
+  Future<void> voidSale({
+    required SaleTransaction transaction,
+    required Map<String, double> stockMovements,
+  }) async {
+    // The customer attached to the cart is the pre-sale snapshot — commitSale
+    // never mutates it, only the separate `updatedCustomer` it computed — so
+    // restoring exactly this row undoes the loyalty movement precisely,
+    // rather than trying to reconstruct it from a delta.
+    final preSaleCustomer = transaction.cart.customer;
+
+    await _store.orders.voidSale(
+      orderId: transaction.id,
+      stockMovements: stockMovements,
+      customerRow: preSaleCustomer == null
+          ? null
+          : CatalogueDao.customerToRow(preSaleCustomer),
+    );
+
+    // Disk is reverted; bring the read caches back in line with it. Negating
+    // the same map reuses cacheStockMovement's "subtract" semantics to add
+    // the stock back instead.
+    _store.cacheStockMovement(
+      stockMovements.map((id, qty) => MapEntry(id, -qty)),
+    );
+    if (preSaleCustomer != null) _store.cacheCustomer(preSaleCustomer);
+    await _store.refreshUnsyncedCount();
+  }
+
   @override
   Future<List<SaleTransaction>> history({int limit = 50}) =>
       _store.orders.recent(limit: limit);