fix: export TruncationConfig from __init__.py

Author: Brandon Meyerowitz

commonbase/__init__.py

@@ -2,6 +2,7 @@
 from commonbase.exceptions import CommonbaseApiException, CommonbaseException
 from commonbase.chat_context import ChatContext, ChatMessage
 from commonbase.provider_config import ProviderConfig, OpenAIParams, AnthropicParams
+from commonbase.truncation_config import TruncationConfig
 
 __all__: [
     "Completion",
@@ -12,4 +13,5 @@
     "ProviderConfig",
     "OpenAIParams",
     "AnthropicParams",
+    "TruncationConfig",
 ]  # type: ignore