Introduce tests to validate the behavior of the Unwrap function for both standard errors and StoneError instances. Ensure correct handling of wrapped errors and verify type identification with IsStoneError checks.
Introduce comprehensive tests for core functionalities including error creation, metadata handling, wrapping, JSON conversion, and type validation. These tests ensure robustness and reliability of the stoneerror package.
Updated module path and significantly extended the StoneError implementation with new functionality, including metadata handling, error wrapping, JSON serialization, and utilities like `IsStoneError`. Enhanced README with detailed examples, usage guidelines, and a thematic introduction.