dotnet-webapi

# ASP.NET Core Web API Produce well-structured ASP.NET Core Web API endpoints with proper HTTP semantics, OpenAPI documentation, and error handling. ## When to Use Use this skill when working on ASP.NET Core HTTP APIs, including: - adding or modifying Web API endpoints implemented with controllers or minimal APIs; - wiring up OpenAPI/Swagger metadata and endpoint documentation; - defining request/response DTOs and consistent HTTP status code behavior; - adding `.http` files or similar request-based API testing artifacts; - configuring centralized API error handling middleware or exception mapping. ## When Not to Use Do not use this skill for: - general C# coding style or non-API refactoring; - EF Core data modeling or query optimization work; use `optimizing-ef-core-queries`; - frontend, Razor, or Blazor UI changes; - gRPC services; - SignalR hubs or real-time messaging flows. ## Inputs / prerequisites Before applying this skill, gather the project context needed to match the existing API style and wiring: - the ASP.NET Core entry point, typically `Program.cs`; - any existing controllers, especially classes inheriting `ControllerBase` or using `[ApiController]`; - any existing minimal API registrations such as `app.MapGet`, `app.MapPost`, `app.MapPut`, or `app.MapDelete`; - related DTO, model, validation, and error-handling types already used by the project; - available build, run, and test commands so changes can be verified. If the user asks for a new endpoin...