add new Z .ai GLM Image support

Author: mythz

content/docs/extensions/built-in.mdx

@@ -42,6 +42,7 @@ Provides support for popular LLM providers requiring custom handling beyond Open
 - [nvidia](https://github.com/ServiceStack/llms/blob/main/llms/extensions/providers/nvidia.py): Integration with NVIDIA's GenAI APIs
 - [openai](https://github.com/ServiceStack/llms/blob/main/llms/extensions/providers/openai.py): Integration with OpenAI's chat and image generation models
 - [openrouter](https://github.com/ServiceStack/llms/blob/main/llms/extensions/providers/openrouter.py): Integration with OpenRouter for image generation
+- [z.ai](https://github.com/ServiceStack/llms/blob/main/llms/extensions/providers/zai.py): Integration with Z.ai for image generation
 
 ### Disable Extensions
 

content/docs/media-generation/image-generation.mdx

@@ -11,6 +11,7 @@ Unlike text generation, there's no standard API for image generation across prov
 | OpenAI     | ✅ Supported |
 | OpenRouter | ✅ Supported |
 | Chutes     | ✅ Supported |
+| Z.ai       | ✅ Supported |
 | Nvidia     | ✅ Supported |
 
 To begin select an image generation model from the Model Selector that supports image generation:

content/docs/v3.mdx

@@ -540,6 +540,7 @@ Unlike text generation, there's no standard API for image generation across prov
 | OpenAI     | ✅ Supported |
 | OpenRouter | ✅ Supported |
 | Chutes     | ✅ Supported |
+| Z.ai       | ✅ Supported |
 | Nvidia     | ✅ Supported |
 
 To begin select an image generation model from the Model Selector that supports image generation: