[V1]SupportsV0Only protocol for model definitions (#13959)

Signed-off-by: Roger Wang <ywang@roblox.com>

vllm/model_executor/models/__init__.py

@@ -1,8 +1,9 @@
 # SPDX-License-Identifier: Apache-2.0
 
 from .interfaces import (HasInnerState, SupportsLoRA, SupportsMultiModal,
-                         SupportsPP, has_inner_state, supports_lora,
-                         supports_multimodal, supports_pp)
+                         SupportsPP, SupportsV0Only, has_inner_state,
+                         supports_lora, supports_multimodal, supports_pp,
+                         supports_v0_only)
 from .interfaces_base import (VllmModelForPooling, VllmModelForTextGeneration,
                               is_pooling_model, is_text_generation_model)
 from .registry import ModelRegistry
@@ -21,4 +22,6 @@ __all__ = [
     "supports_multimodal",
     "SupportsPP",
     "supports_pp",
+    "SupportsV0Only",
+    "supports_v0_only",
 ]