[Bugfix] Limit Qwen-Image-Edit-2511 input image count (#2840)

Signed-off-by: david6666666 <530634352@qq.com>
Co-authored-by: Gao Han <hgaoaf@connect.ust.hk>

tests/test_diffusion_config_propagation.py

@@ -15,6 +15,7 @@ from vllm_omni.diffusion.data import (
     DiffusionParallelConfig,
     OmniDiffusionConfig,
 )
+from vllm_omni.diffusion.model_metadata import QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
 
@@ -109,3 +110,12 @@ class TestCreateDefaultDiffusion:
         ea = stages[0]["engine_args"]
         assert ea["enforce_eager"] is True
         assert ea["lora_path"] == "/tmp/lora"
+
+
+def test_qwen_image_edit_plus_sets_generic_multimodal_limit():
+    od_config = OmniDiffusionConfig(model="Qwen/Qwen-Image-Edit-2511", model_class_name="QwenImageEditPlusPipeline")
+
+    od_config.update_multimodal_support()
+
+    assert od_config.supports_multimodal_inputs is True
+    assert od_config.max_multimodal_image_inputs == QWEN_IMAGE_EDIT_PLUS_MAX_INPUT_IMAGES