### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### The Feature

## Summary

Please add native image generation support for Alibaba Cloud DashScope / Model Studio image models, including Qwen-Image and Wan text-to-image models, in LiteLLM's `/v1/images/generations` endpoint.

This is related to the previous issue:

- https://github.com/BerriAI/litellm/issues/25319

However, that issue was closed without actually adding native DashScope image generation support. The underlying issue still exists: LiteLLM currently does not have a DashScope image generation provider adapter.

Official Alibaba Cloud documentation:

https://www.alibabacloud.com/help/zh/model-studio/text-to-image?spm=a2c63.p38356.help-menu-2400256.d_0_3_2_0.43d27032PZcjYN#2e3d0267bdazi

Alibaba Cloud Model Studio provides image generation models such as:

- `qwen-image` - `qwen-image-plus` - `qwen-image-max` - `qwen-image-2.0-pro` - Wan text-to-image models

These models are available through DashScope native APIs, but they currently cannot be used cleanly through LiteLLM's OpenAI-compatible `/v1/images/generations` endpoint.

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## Why this is no…