Use fully-qualified KitchenReceipt namespace for Gang, Dish, and
DishModifications in BuildSampleKitchenReceipt and
BuildSampleKitchenReceiptNextDish to resolve CS0104 errors caused by
identical type names in BarReceipt and KitchenReceipt namespaces.
Add global.json to pin SDK to .NET 8.0 for compatibility with .slnx.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
