[LoRA][Spec Decode] Support LoRA for Nemotron-H MTP models (#32265)

Signed-off-by: Daniel Serebrenik <daserebrenik@nvidia.com>
Co-authored-by: Jee Jee Li <pandaleefree@gmail.com>

vllm/model_executor/models/interfaces.py

@@ -521,6 +521,8 @@ class SupportsLoRA(Protocol):
     # are empty by default.
     embedding_modules: ClassVar[dict[str, str]] = {}
     packed_modules_mapping: dict[str, list[str]] = {}
+    # Module prefixes to skip during LoRA loading (e.g., ["mtp."] for MTP layers)
+    lora_skip_prefixes: ClassVar[list[str]] = []
 
 
 # We can't use runtime_checkable with ClassVar for issubclass checks