ver. 0.292: ShopProduct + ShopPaymentMethod + ShopPromotion + ShopStatuses + ShopTransport frontend migration to Domain

Full migration of front\factory\ — entire directory removed (all 20 classes migrated).
ProductRepository +20 frontend methods, PromotionRepository +5 applyType methods,
TransportRepository +4 cached methods, PaymentMethodRepository +cached frontend methods.
Fix: broken transports_list() in ajax.php replaced with forPaymentMethod().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/stubs/ShopProduct.php

@@ -0,0 +1,18 @@
+<?php
+namespace shop;
+
+/**
+ * Stub klasy shop\Product na potrzeby testów jednostkowych.
+ */
+class Product
+{
+    public static function is_product_on_promotion($productId)
+    {
+        return false;
+    }
+
+    public static function get_product_price($productId)
+    {
+        return 0;
+    }
+}