[Feature] HunyuanImage-3.0 IT2I: multi-image input + prompt API cleanup (#3444)

Signed-off-by: TaffyOfficial <2324465096@qq.com>
Signed-off-by: TaffyOfficial <wu15922848573@outlook.com>
Signed-off-by: skf1999 <13234016272@163.com>
Signed-off-by: zuiho <2324465096@qq.com>
Signed-off-by: Claude Code <noreply@anthropic.com>
Signed-off-by: zuiho <wu15922848573@outlook.com>
Signed-off-by: TaffyOfficial <2587297563@qq.com>
Co-authored-by: TaffyOfficial <2324465096@qq.com>
Co-authored-by: TaffyOfficial <wu15922848573@outlook.com>
Co-authored-by: skf1999 <13234016272@163.com>

vllm_omni/diffusion/model_metadata.py

@@ -13,6 +13,8 @@ class DiffusionModelMetadata:
 
 
 QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES = 4
+# Upstream HunyuanImage-3.0 "Multi-Image Fusion" caps reference images at 3.
+HUNYUAN_IMAGE3_MAX_INPUT_IMAGES = 3
 
 
 _DIFFUSION_MODEL_METADATA: dict[str, DiffusionModelMetadata] = {
@@ -20,6 +22,10 @@ _DIFFUSION_MODEL_METADATA: dict[str, DiffusionModelMetadata] = {
         supports_multimodal_inputs=True,
         max_multimodal_image_inputs=QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES,
     ),
+    "HunyuanImage3Pipeline": DiffusionModelMetadata(
+        supports_multimodal_inputs=True,
+        max_multimodal_image_inputs=HUNYUAN_IMAGE3_MAX_INPUT_IMAGES,
+    ),
 }