This pull request introduces several breaking changes and new features in preparation for version 5.0.0. The main focus is on improving testability, resource management, and request cancellation support across the client library. The most significant updates include making wrapper constructors internal, introducing a new client interface for easier mocking, implementing IDisposable for proper HTTP resource cleanup, and adding optional CancellationToken parameters to client methods.

Breaking changes and API surface improvements

• Wrapper classes (e.g., CustomerWrapper, ProductWrapper) can no longer be constructed directly; their constructors are now internal and require an HttpClient instance, enforcing usage through FacturapiClient. (FacturapiClient.cs, Wrappers/CustomerWrapper.cs, Wrappers/CatalogWrapper.cs, [1] [2] [3]
• Introduced the IFacturapiClient interface, allowing consumers to mock the client for testing purposes. (IFacturapiClient.cs, IFacturapiClient.csR1-R18)
• FacturapiClient now implements IDisposable. Consumers should call Dispose() or use a using statement to ensure HTTP resources are released promptly. (FacturapiClient.cs, [1] [2]

Request cancellation and async improvements

• All async methods in wrapper classes now accept optional CancellationToken parameters, enabling callers to cancel in-flight requests. (Wrappers/CustomerWrapper.cs, Wrappers/CatalogWrapper.cs, [1] [2]
• Internal HTTP calls and error handling have been updated to propagate cancellation tokens and throw if cancellation is requested. (Wrappers/BaseWrapper.cs, [1] [2]

Documentation and versioning

• Updated CHANGELOG.md to reflect the new version (5.0.0), highlight breaking changes, and document the new features and improvements. [1] [2]