[Example] Migrate HunyuanImage-3.0 to model_extras + shared task examples (#5559)

Signed-off-by: suyanli220 <suyanli220@gmail.com>
Signed-off-by: suyan.li <suyan.li@bytedance.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: suyan.li <suyan.li@bytedance.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

docs/user_guide/examples/offline_inference/hunyuan_image3.md

@@ -1,35 +0,0 @@
-# HunyuanImage-3.0 Image-to-Text Inference
-
-Source <https://github.com/vllm-project/vllm-omni/tree/main/examples/offline_inference/hunyuan_image3>.
-
-
-This example demonstrates how to run HunyuanImage-3.0 Image-to-Text with the vLLM-Omni.
-
-## Local CLI Usage
-
-Download the example image:
-
-```bash
-wget https://vllm-public-assets.s3.us-west-2.amazonaws.com/vision_model_images/cherry_blossom.jpg
-```
-
-Run example:
-
-```bash
-python image_to_text.py \
-  --image cherry_blossom.jpg \
-  --prompt "<|startoftext|>You are an assistant that understands images and outputs text.<img>Describe the content of the picture."
-```
-
-Key arguments:
-
-- `--model`: Model used. Default is: tencent/HunyuanImage-3.0-Instruct (Optional).
-- `--image`: Path to input image (required).
-- `--prompt`: Text description used to guide image understanding (required).
-
-## Example materials
-
-??? abstract "image_to_text.py"
-    ``````py
-    --8<-- "examples/offline_inference/hunyuan_image3/image_to_text.py"
-    ``````