Add π0 VLA model support (#4222)

Signed-off-by: Yichen Wang <yichen.wang@bytedance.com>
Signed-off-by: Didan Deng <33117903+wtomin@users.noreply.github.com>
Co-authored-by: Didan Deng <33117903+wtomin@users.noreply.github.com>

vllm_omni/diffusion/data.py

@@ -1318,6 +1318,12 @@ class OmniDiffusionConfig:
                         self.update_multimodal_support()
                     else:
                         raise
+                elif cfg.get("type") == "pi0":
+                    # π0 (Pi-Zero) VLA — the LeRobot config.json uses ``type: "pi0"``.
+                    if self.model_class_name is None:
+                        self.model_class_name = "Pi0Pipeline"
+                    self.set_tf_model_config(TransformerConfig())
+                    self.update_multimodal_support()
                 elif architectures and len(architectures) == 1:
                     architecture = architectures[0]
                     from vllm_omni.diffusion.registry import DiffusionModelRegistry