[Diffusion] add GR00T-N1.7 pipeline with OpenPI serving (#3798)

Signed-off-by: Zhengyuan Su <su.zhengyuan@u.nus.edu>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

vllm_omni/model_executor/models/gr00t/__init__.py

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project

vllm_omni/model_executor/models/gr00t/pipeline.py

@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""GR00T N1.7 single-stage policy topology."""
+
+from vllm_omni.config.stage_config import (
+    PipelineConfig,
+    StageExecutionType,
+    StagePipelineConfig,
+)
+
+GR00T_N1D7_PIPELINE = PipelineConfig(
+    model_type="Gr00tN1d7",
+    model_arch="Gr00tN1d7Pipeline",
+    hf_architectures=("Gr00tN1d7",),
+    stages=(
+        StagePipelineConfig(
+            stage_id=0,
+            model_stage="diffusion",
+            execution_type=StageExecutionType.DIFFUSION,
+            input_sources=(),
+            final_output=True,
+            final_output_type="actions",
+            model_arch="Gr00tN1d7Pipeline",
+        ),
+    ),
+)