[Feature Request] Supports Z-Image-Turbo on onnxruntime-webgpu

### Describe the feature request

`Z-Image-Turbo`[1] is a high-performance image generation model featuring 6B parameters. It has recently gained significant traction, reaching the top spot on the Hugging Face trending list.

This issue is opened to discuss the enabling of Z-Image-Turbo for onnxruntime-webgpu.

[1] https://huggingface.co/Tongyi-MAI/Z-Image-Turbo

### Describe scenario use case

Image generation using onnxruntime-webgpu

Start with the Z-Image-Turbo model card linked in the issue and the onnxruntime-webgpu integration. No source file, test, or entry point is named, so first identify the relevant support boundary and a reproducible image-generation validation case. Done means Z-Image-Turbo runs successfully in the stated scenario.

Written by the indexing model from the issue text.