Commits for 2025-10-29

The following 4 changes have been made on 2025-10-29:

- added product related traits, better generate product logic, now using new traits, added physical fields to book model, initial code to implement matrixrate shipping method (Author: Mirko De Grandis, Hash: #ef1e7f3)
- added freeshipping shipping method, added BaseShippingMethod/BasePaymentMethod abstract classes, better logic in shipping page (Author: Mirko De Grandis, Hash: #07fb4b3)
- commit (Author: Mirko De Grandis, Hash: #5fbb50c)
- added shipping methods, added book model to test shipping costs (Author: Mirko De Grandis, Hash: #8a93ec0)

Check it out. More are coming soon!