Advanced Generics for Flexible Type-Safe Configuration Management

Design a type-safe configuration management system using TypeScript generics that supports nested configuration objects with runtime validation, compile-time type checking, and environment-specific overrides. Create a generic configuration loader that can handle different config structures while maintaining strict type safety, with built-in support for default values, required/optional fields, and automatic type inference. Implement methods to merge configurations, validate against a schema, and provide intelligent type narrowing across different environment contexts.