Added XML documentation to extension and handler classes for improved maintainability. Refactored repository access to use .Query instead of .ReadOnly() for consistency. Updated async extension methods for better readability and error handling.
Removed Obsolete attributes from FirstAsync and Exceptions class. Changed FirstAsync return type to non-nullable Task<T> and updated its logic to throw the provided exception when the sequence is empty, instead of returning null.
Added FirstAsync<T, TException> as an obsolete extension method for Task<IEnumerable<T>>. This method returns the first element or throws a custom exception if the result is null, using a provided factory delegate. Intended for legacy .NET projects.
Marked TaskExtensions class and all its methods as [Obsolete] with guidance to implement Mediator behaviors instead. Added new [Obsolete] extension methods for null/empty checks and chaining. Introduced an [Obsolete] Exceptions class with factory methods for common exceptions. All changes are intended for legacy or transitional use only.
