Refactor Stripe payment handling and order status

Refactored Stripe payment integration to use a dedicated Stripe model for session data, updating the PaymentSerializer accordingly. Renamed Order.Status to Order.OrderStatus for clarity. Updated configuration app to ensure SiteConfiguration singleton is created post-migration. Removed obsolete seed_app_config command from docker-compose. Adjusted frontend API generated files and moved orval config.

backend/commerce/models.py

@@ -104,7 +104,7 @@ class ProductImage(models.Model):
 # ------------------ OBJEDNÁVKY ------------------
 
 class Order(models.Model):
-    class Status(models.TextChoices):
+    class OrderStatus(models.TextChoices):
         CREATED = "created", "cz#Vytvořeno"
         CANCELLED = "cancelled", "cz#Zrušeno"
         COMPLETED = "completed", "cz#Dokončeno"
@@ -113,7 +113,7 @@ class Order(models.Model):
         REFUNDED = "refunded", "cz#Vráceno"
 
     status = models.CharField(
-        max_length=20, choices=Status.choices, null=True, blank=True, default=Status.CREATED
+        max_length=20, choices=OrderStatus.choices, null=True, blank=True, default=OrderStatus.CREATED
     )
 
     # Stored order grand total; recalculated on save