refactor: organize code by domain-driven design

Refactoriza la estructura del proyecto siguiendo principios de Domain-Driven Design,
organizando serializers, API views y servicios por dominios de negocio.

Cambios principales:

## Serializers (serializers/)
- Dividido serializers.py en módulos por dominio:
  * products.py: ProductSerializer, ListProductSerializer
  * customers.py: CustomerSerializer, ListCustomerSerializer
  * sales.py: SaleSerializer, SaleLineSerializer, CatalogSaleSerializer, etc.
  * payments.py: ReconciliationJarSerializer, PaymentMethodSerializer
  * __init__.py: Exporta todos los serializers para mantener compatibilidad

## API Views (api/)
- Dividido api_views.py en módulos por dominio:
  * products.py: ProductView, ProductsFromTrytonView
  * customers.py: CustomerView, CustomersFromTrytonView
  * sales.py: SaleView, CatalogSaleView, SaleSummary, SalesForTrytonView, SalesToTrytonView
  * payments.py: ReconciliateJarView, ReconciliateJarModelView, PaymentMethodView, SalesForReconciliationView
  * admin.py: AdminCodeValidateView
  * __init__.py: Exporta todas las vistas para facilitar importaciones

## Services Layer (services/tryton/)
- Nueva capa de servicios para lógica de negocio Tryton:
  * client.py: get_tryton_client(), TrytonSale, TrytonLineSale, configuración
  * products.py: ProductTrytonService - sincronización de productos
  * customers.py: CustomerTrytonService - sincronización de clientes
  * sales.py: SaleTrytonService - sincronización de ventas
  * __init__.py: Exporta servicios y utilidades

## Actualización de URLs
- Actualizado urls.py para importar desde nuevos módulos
- Mantiene todas las rutas existentes sin cambios

## Eliminación de archivos antiguos
- Eliminado serializers.py (refactorizado a serializers/)
- Eliminado api_views.py (refactorizado a api/)

## Beneficios
✅ Cohesión: Código organizado por dominio de negocio
✅ Separación de responsabilidades: API, Serializers y Services separados
✅ Mantenibilidad: Archivos más pequeños y enfocados
✅ Escalabilidad: Fácil agregar nuevos dominios
✅ Testabilidad: Mejor organización para pruebas por dominio
✅ Reutilización: Servicios Tryton pueden usarse desde cualquier vista

## Estructura final:
- models/ (ya existía organizado por dominio)
- serializers/ (nuevo, organizado por dominio)
- api/ (nuevo, organizado por dominio)
- services/tryton/ (nuevo, capa de servicios)

Tests: 46 tests pasando ✓

tienda_ilusion/don_confiao/serializers/__init__.py

@@ -0,0 +1,35 @@
+from .products import ProductSerializer, ListProductSerializer
+from .customers import CustomerSerializer, ListCustomerSerializer
+from .sales import (
+    SaleSerializer,
+    SaleLineSerializer,
+    CatalogSaleSerializer,
+    CatalogSaleLineSerializer,
+    SummarySaleLineSerializer,
+    SaleSummarySerializer,
+    SaleForRenconciliationSerializer,
+)
+from .payments import (
+    ReconciliationJarSerializer,
+    PaymentMethodSerializer,
+)
+
+__all__ = [
+    # Products
+    "ProductSerializer",
+    "ListProductSerializer",
+    # Customers
+    "CustomerSerializer",
+    "ListCustomerSerializer",
+    # Sales
+    "SaleSerializer",
+    "SaleLineSerializer",
+    "CatalogSaleSerializer",
+    "CatalogSaleLineSerializer",
+    "SummarySaleLineSerializer",
+    "SaleSummarySerializer",
+    "SaleForRenconciliationSerializer",
+    # Payments
+    "ReconciliationJarSerializer",
+    "PaymentMethodSerializer",
+]

tienda_ilusion/don_confiao/serializers/customers.py

@@ -0,0 +1,15 @@
+from rest_framework import serializers
+
+from ..models.customers import Customer
+
+
+class CustomerSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Customer
+        fields = ["id", "name", "address", "email", "phone", "external_id"]
+
+
+class ListCustomerSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Customer
+        fields = ["id", "name"]

tienda_ilusion/don_confiao/serializers/payments.py

@@ -0,0 +1,31 @@
+from rest_framework import serializers
+
+from ..models.payments import ReconciliationJar, PaymentMethods
+from .sales import SaleSerializer
+
+
+class ReconciliationJarSerializer(serializers.ModelSerializer):
+    Sales = SaleSerializer(many=True, read_only=True)
+
+    class Meta:
+        model = ReconciliationJar
+        fields = [
+            "id",
+            "date_time",
+            "reconcilier",
+            "cash_taken",
+            "cash_discrepancy",
+            "total_cash_purchases",
+            "Sales",
+        ]
+
+
+class PaymentMethodSerializer(serializers.Serializer):
+    text = serializers.CharField()
+    value = serializers.CharField()
+
+    def to_representation(self, instance):
+        return {
+            "text": instance[1],
+            "value": instance[0],
+        }

tienda_ilusion/don_confiao/serializers/products.py

@@ -0,0 +1,23 @@
+from rest_framework import serializers
+
+from ..models.products import Product, ProductCategory
+
+
+class ProductSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Product
+        fields = [
+            "id",
+            "name",
+            "active",
+            "price",
+            "measuring_unit",
+            "categories",
+            "external_id",
+        ]
+
+
+class ListProductSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Product
+        fields = ["id", "name"]

tienda_ilusion/don_confiao/serializers/sales.py

@@ -0,0 +1,104 @@
+from rest_framework import serializers
+
+from ..models.sales import (
+    Sale,
+    SaleLine,
+    CatalogSale,
+    CatalogSaleLine,
+    Payment,
+)
+from .products import ListProductSerializer
+from .customers import ListCustomerSerializer
+
+
+class SaleLineSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = SaleLine
+        fields = ["id", "sale", "product", "unit_price", "quantity"]
+
+
+class SaleSerializer(serializers.ModelSerializer):
+    total = serializers.ReadOnlyField(source="get_total")
+
+    class Meta:
+        model = Sale
+        fields = [
+            "id",
+            "customer",
+            "date",
+            "saleline_set",
+            "total",
+            "payment_method",
+            "external_id",
+        ]
+
+
+class CatalogSaleLineSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = CatalogSaleLine
+        read_only_fields = ["catalog_sale"]
+        fields = [
+            "id",
+            "catalog_sale",
+            "product",
+            "unit_price",
+            "quantity",
+        ]
+
+
+class CatalogSaleSerializer(serializers.ModelSerializer):
+    catalogsaleline_set = CatalogSaleLineSerializer(many=True, required=False)
+    total = serializers.ReadOnlyField(source="get_total")
+
+    class Meta:
+        model = CatalogSale
+        fields = [
+            "id",
+            "customer",
+            "date",
+            "catalogsaleline_set",
+            "total",
+        ]
+
+    def create(self, validated_data):
+        lines_data = validated_data.pop("catalogsaleline_set", [])
+        catalog_sale = CatalogSale.objects.create(**validated_data)
+
+        for line_data in lines_data:
+            CatalogSaleLine.objects.create(catalog_sale=catalog_sale, **line_data)
+
+        return catalog_sale
+
+
+class SummarySaleLineSerializer(serializers.ModelSerializer):
+    product = ListProductSerializer()
+
+    class Meta:
+        model = SaleLine
+        fields = ["product", "quantity", "unit_price", "description"]
+
+
+class SaleSummarySerializer(serializers.ModelSerializer):
+    customer = ListCustomerSerializer()
+    lines = SummarySaleLineSerializer(many=True, source="saleline_set")
+
+    class Meta:
+        model = Sale
+        fields = ["id", "date", "customer", "payment_method", "lines"]
+
+
+class SaleForRenconciliationSerializer(serializers.Serializer):
+    id = serializers.IntegerField()
+    date = serializers.DateTimeField()
+    payment_method = serializers.CharField()
+    customer = serializers.SerializerMethodField()
+    total = serializers.SerializerMethodField()
+
+    def get_customer(self, sale):
+        return {
+            "id": sale.customer.id,
+            "name": sale.customer.name,
+        }
+
+    def get_total(self, sale):
+        return sale.get_total()