Removed the deprecated State class and its properties from the codebase. Also removed State from the dependency injection configuration, as it is no longer used.
DbConfig is no longer registered as a singleton in the dependency injection setup. This prevents accidental injection and avoids runtime NotImplementedException errors. The related comment about service lifetimes remains for future review.
Renamed the ServiceCollectionExtensions class to DependencyInjection to better reflect its purpose and possibly consolidate dependency injection methods. No functional changes were made.
