Implements use cases for C# and Blazor (.NET 10) applications using a Vertical Slice Architecture. Takes a UC-XXX.md specification and generates feature-folder components, C# Commands/Queries with their handlers and validators, EF Core entities/configurations, and Blazor (Razor) pages/components, with UC-XXX BR-YYY markers on every business rule. Use when the user asks to "implement a use case in C#", "implement UC-001 in .NET", "build a Blazor page", "create a Razor component for this use case", "create a Vertical Slice", or mentions Blazor, Razor, .NET 10, or a feature slice for a use case specification.