Refactor commerce models and add configuration app

Major refactor of commerce models: restructured Carrier, Payment, and DiscountCode models, improved order total calculation, and integrated Zasilkovna and Stripe logic. Added new configuration Django app for shop settings, updated Zasilkovna and Stripe models, and fixed Zasilkovna client WSDL URL. Removed unused serializers and views in commerce, and registered new apps in settings.

backend/commerce/serializers.py

@@ -2,89 +2,3 @@ from rest_framework import serializers
 from drf_spectacular.utils import extend_schema_field
 from .models import Category, Product, ProductImage, DiscountCode, Order, OrderItem, Carrier
 
-# NOTE: Carrier intentionally skipped per request (TODO below)
-
-class CategorySerializer(serializers.ModelSerializer):
-	class Meta:
-		model = Category
-		fields = ["id", "name", "url", "parent", "description", "image"]
-
-
-class ProductImageSerializer(serializers.ModelSerializer):
-	class Meta:
-		model = ProductImage
-		fields = ["id", "image", "alt_text", "is_main"]
-
-
-class ProductSerializer(serializers.ModelSerializer):
-	images = ProductImageSerializer(many=True, read_only=True)
-	available = serializers.BooleanField(read_only=True)
-
-	class Meta:
-		model = Product
-		fields = [
-			"id","name","description","code","category","price","currency","url","stock","is_active","limited_to","default_carrier","available","images","created_at","updated_at"
-		]
-		read_only_fields = ["created_at","updated_at","available"]
-
-
-class DiscountCodeSerializer(serializers.ModelSerializer):
-	is_valid = serializers.SerializerMethodField()
-
-	class Meta:
-		model = DiscountCode
-		fields = ["id","code","description","percent","amount","valid_from","valid_to","active","usage_limit","used_count","specific_products","specific_categories","is_valid"]
-		read_only_fields = ["used_count","is_valid"]
-
-	def get_is_valid(self, obj):
-		return obj.is_valid()
-
-
-class OrderItemSerializer(serializers.ModelSerializer):
-	product = serializers.PrimaryKeyRelatedField(queryset=Product.objects.all())
-	line_total = serializers.SerializerMethodField()
-
-	class Meta:
-		model = OrderItem
-		fields = ["id","product","quantity","line_total"]
-		read_only_fields = ["line_total"]
-
-	def get_line_total(self, obj):
-		# Uses existing model logic for discount via order context (kept minimal)
-		# Since discount resolution logic is custom & currently incomplete, just returns base price * qty
-		return obj.product.price * obj.quantity
-
-
-class OrderSerializer(serializers.ModelSerializer):
-	items = OrderItemSerializer(many=True)
-	total_price = serializers.DecimalField(max_digits=10, decimal_places=2, read_only=True)
-
-	class Meta:
-		model = Order
-		fields = [
-			"id","user","status","total_price","currency","first_name","last_name","email","phone","address","city","postal_code","country","note","discount","items","created_at","updated_at"
-		]
-		read_only_fields = ["total_price","created_at","updated_at"]
-
-	def create(self, validated_data):
-		items_data = validated_data.pop("items", [])
-		order = Order.objects.create(**validated_data)
-		for item in items_data:
-			OrderItem.objects.create(order=order, **item)
-		order.total_price = order.calculate_total_price() if hasattr(order, "calculate_total_price") else order.total_price
-		order.save()
-		return order
-
-	def update(self, instance, validated_data):
-		items_data = validated_data.pop("items", None)
-		for attr, value in validated_data.items():
-			setattr(instance, attr, value)
-		if items_data is not None:
-			instance.items.all().delete()
-			for item in items_data:
-				OrderItem.objects.create(order=instance, **item)
-		instance.total_price = instance.calculate_total_price() if hasattr(instance, "calculate_total_price") else instance.total_price
-		instance.save()
-		return instance
-
-# TODO: CarrierSerializer (Carrier API not requested yet)