Production-grade C#/.NET patterns for APIs, MCP servers, and enterprise backends with modern async, DI, and data access practices.

• Covers clean architecture project structure, dependency injection lifetimes, and configuration with IOptions pattern
• Async/await best practices including parallel execution, ConfigureAwait usage, and ValueTask optimization for hot paths
• Entity Framework Core and Dapper repository patterns with query optimization, multi-mapping, and performance considerations
• Multi-level caching with Redis and memory cache, including stale-while-revalidate and cache invalidation strategies
• Unit and integration testing with xUnit, Moq, and WebApplicationFactory; Result pattern for flow control without exceptions