Building ASP.NET Core APIs & apps

Description

Build, advise on, and review ASP.NET Core web APIs and apps — Minimal APIs vs controllers, route groups, TypedResults, input validation, ProblemDetails error handling, authentication and policy/resource-based authorization, middleware order, CORS, rate limiting, OpenAPI, options/configuration, HttpClientFactory, health checks, output caching, observability, and production hardening. Use whenever a project references Microsoft.AspNetCore / Microsoft.NET.Sdk.Web, has Program.cs with WebApplication.CreateBuilder, or the user builds or reviews a .NET API, endpoint, middleware, or auth setup.