Fix #1325 Export MultiProvider in top level package (#1326)

Author: kobol

src/agents/__init__.py

@@ -43,6 +43,7 @@
 from .memory import Session, SQLiteSession
 from .model_settings import ModelSettings
 from .models.interface import Model, ModelProvider, ModelTracing
+from .models.multi_provider import MultiProvider
 from .models.openai_chatcompletions import OpenAIChatCompletionsModel
 from .models.openai_provider import OpenAIProvider
 from .models.openai_responses import OpenAIResponsesModel
@@ -171,6 +172,7 @@ def enable_verbose_stdout_logging():
     "ModelTracing",
     "ModelSettings",
     "OpenAIChatCompletionsModel",
+    "MultiProvider",
     "OpenAIProvider",
     "OpenAIResponsesModel",
     "AgentOutputSchema",