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## 2.13.0

**`(feat):`** Generate interfaces for all SDK clients to enable dependency injection and mocking for unit testing.

Each client class now implements a corresponding interface:

* Root client implements `I{ClientName}` (e.g., `IAcmeClient`)
* Sub-package clients implement `I{SubpackageName}Client` (e.g., `IUsersClient`)

This allows consumers to:

* Use dependency injection frameworks to inject client interfaces
* Mock client interfaces in unit tests using libraries like Moq or NSubstitute
* Follow SOLID principles with interface-based programming