Introduces a OneToOneField for carrier in the Refund model to support future integration and refactoring. Adds and updates TODO comments for email template usage, error handling in Stripe webhooks, and clarifies logic placement in Stripe models.
Refactored commerce models to support refunds, invoices, and improved carrier/payment logic. Added new serializers and viewsets for products, categories, images, discount codes, and refunds. Introduced Stripe client integration and removed legacy Stripe admin/model code. Updated Dockerfile for PDF generation dependencies. Removed obsolete migration files and updated configuration app initialization. Added invoice template and tasks for order cleanup.
