Introduces RefundPublicView for public refund creation via email and invoice/order ID, returning refund info and a base64-encoded PDF slip. Adds RefundCreatePublicSerializer for validation and creation, implements PDF generation in Refund model, and provides a customer-facing HTML template for the return slip. Updates URLs to expose the new endpoint.
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.
