config block, layout ignored

File contains the following section

``` d2
vars: {
	d2-config: {
		layout-engine: elk
	}
}
```
However, the preview is still rendered using the system setting

<img width="385" height="106" alt="Image" src="https://github.com/user-attachments/assets/99897112-2a12-4b5a-b56d-ffa0f6ca543d" />

File config should override system setting