Lazy load OpenAILikeChatConfig to avoid heavy import (#18075)

- Remove direct import of OpenAILikeChatConfig from llms.openai_like.chat.handler
- Add OpenAILikeChatConfig to LLM_CONFIG_NAMES for lazy loading
- Add handler in _lazy_import_llm_configs() to lazy load when accessed
- Add OpenAILikeChatConfig to TYPE_CHECKING block for type hints

This defers the import until OpenAILikeChatConfig is actually needed, improving import time.

litellm/__init__.py

@@ -1056,7 +1056,6 @@ from .utils import client
 
 from .llms.bytez.chat.transformation import BytezChatConfig
 from .llms.custom_llm import CustomLLM
-from .llms.openai_like.chat.handler import OpenAILikeChatConfig
 from .llms.aiohttp_openai.chat.transformation import AiohttpOpenAIChatConfig
 from .llms.galadriel.chat.transformation import GaladrielChatConfig
 from .llms.github.chat.transformation import GithubChatConfig
@@ -1554,6 +1553,7 @@ if TYPE_CHECKING:
 
     # LLM config classes - lazy loaded only
     AmazonConverseConfig: Type[Any]
+    OpenAILikeChatConfig: Type[Any]
 
 
 def __getattr__(name: str) -> Any:

litellm/_lazy_imports.py

@@ -157,6 +157,7 @@ DOTPROMPT_NAMES = (
 # LLM config classes that support lazy loading via _lazy_import_llm_configs
 LLM_CONFIG_NAMES = (
     "AmazonConverseConfig",
+    "OpenAILikeChatConfig",
 )
 
 # Types that support lazy loading via _lazy_import_types
@@ -651,4 +652,12 @@ def _lazy_import_llm_configs(name: str) -> Any:
         _globals["AmazonConverseConfig"] = _AmazonConverseConfig
         return _AmazonConverseConfig
 
+    if name == "OpenAILikeChatConfig":
+        from .llms.openai_like.chat.handler import (
+            OpenAILikeChatConfig as _OpenAILikeChatConfig,
+        )
+
+        _globals["OpenAILikeChatConfig"] = _OpenAILikeChatConfig
+        return _OpenAILikeChatConfig
+
     raise AttributeError(f"LLM config lazy import: unknown attribute {name!r}")