Modern .NET 10 and C# 14 patterns for minimal APIs, modular monoliths, and resilient applications.

• Covers C# 14 syntax (extension blocks, field keyword, null-conditional assignment) and .NET 10 minimal APIs with validation, TypedResults, and modular architecture
• Includes security patterns: JWT authentication, CORS, rate limiting, middleware ordering, and RFC 9457 problem details
• Provides infrastructure guidance on Options pattern variants (IOptions, IOptionsSnapshot, IOptionsMonitor), HTTP resilience with standard handlers, Channels, health checks, and EF Core
• Documents mandatory patterns (always use TypedResults, ValidateOnStart, UtcNow) and anti-patterns to avoid (manual HttpClient, blocking async, N+1 queries)
• Includes integration testing with WebApplicationFactory and recommended libraries (MediatR, FluentValidation, Mapster, ErrorOr, Polly, Serilog)