dotnet-input-validation Comprehensive input validation patterns for .NET APIs. Covers the .NET 10 built-in validation system, FluentValidation for complex business rules, Data Annotations for simple models, endpoint filters for Minimal API integration, ProblemDetails error responses, and security-focused validation techniques. Scope boundary: This skill owns practical validation framework guidance -- when to use each framework, how to configure and integrate them, and security-focused input handling tips. OWASP security principles (injection categories, threat modeling) -- see [skill:dotnet-s…