fix(sglang): sglang requires nest_asyncio patch

Author: guicho271828

mellea/backends/sglang.py

@@ -17,6 +17,7 @@
 from collections.abc import Callable
 from typing import TYPE_CHECKING, Any, Optional
 
+import nest_asyncio
 import sglang as sgl  # type:ignore
 from sglang.utils import async_stream_and_merge  # type:ignore
 from transformers import AutoTokenizer, PreTrainedTokenizerBase
@@ -45,6 +46,8 @@
 from mellea.stdlib.chat import Message
 from mellea.stdlib.requirement import LLMaJRequirement, Requirement
 
+nest_asyncio.apply()
+
 
 class LocalSGLangBackend(FormatterBackend):
     """The LocalSGLangBackend uses SGLang's python offline inference interface, and uses a Formatter to convert `Component`s into prompts.