A Spine example that describes the `set_ik_target` function.

**Describe the example you'd like**
I want to add an example that shows the `set_ik_target` function. To clarify how a developer can manipulate a spine bone using Defold Game Object.

**Additional context (optional)**
I want to use this simple setup for that.

<img width="500" height="565" alt="Image" src="https://github.com/user-attachments/assets/e55db5d6-20dd-4103-86e7-3fbba0291434" />
