New Validations

[robinmanuelthiel]

This pull request introduces a minor bug fix and validation improvement to the basket service. The main updates are the addition of a default image URL for basket items and enhanced validation for negative unit prices.

Basket item enhancements:

• Added a default PictureUrl ("http://mypictures/demo.jpg") to each item when mapping to a CustomerBasket in BasketService.cs to ensure items always have an image.

Validation improvements:

• Updated BasketItem validation to add an error if UnitPrice is negative, improving data integrity. The error message is in German: "Unit Preis muss grösser als null sein".

Code cleanup:

• Reordered using statements in BasketService.cs for better organization.

[Copilot]

Pull Request Overview

This PR introduces new validations to the basket functionality by adding unit price validation and reorganizing imports.

• Adds validation for negative unit prices in BasketItem
• Reorders using statements in BasketService for better organization
• Adds a hardcoded picture URL to basket item mapping

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Basket.API/Model/BasketItem.cs	Adds validation to prevent negative unit prices
src/Basket.API/Grpc/BasketService.cs	Reorders imports and adds hardcoded picture URL to basket items

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