feat: add message_types filter to list messages endpoint (#8280)

* feat: add message_types filter to list messages endpoint

Add the ability to filter messages by type when listing message history
via GET /v1/agents/{agent_id}/messages. This brings parity with the
create message endpoint which already supports include_return_message_types.

Changes:
- Add message_types query parameter to list_messages endpoint in agents.py
- Add message_types parameter to get_agent_recall_async in server.py
- Filter messages by message_type after LettaMessage conversion
- Add test for message_types filtering

Closes #8277

Written by Cameron ◯ Letta Code

> "Simplicity is the ultimate sophistication." - Leonardo da Vinci

🐙 Generated with [Letta Code](https://letta.com)

Co-Authored-By: Letta <noreply@letta.com>

* chore: regenerate OpenAPI spec and SDK for message_types filter

🐧 Generated with [Letta Code](https://letta.com)

Co-Authored-By: Letta <noreply@letta.com>

Written by Cameron ◯ Letta Code

"The only way to do great work is to love what you do." - Steve Jobs

---------

Co-authored-by: Letta <noreply@letta.com>

letta/server/server.py

@@ -817,6 +817,7 @@ class SyncServer(object):
         assistant_message_tool_name: str = constants.DEFAULT_MESSAGE_TOOL,
         assistant_message_tool_kwarg: str = constants.DEFAULT_MESSAGE_TOOL_KWARG,
         include_err: Optional[bool] = None,
+        message_types: Optional[List[MessageType]] = None,
     ) -> Union[List[Message], List[LettaMessage]]:
         records = await self.message_manager.list_messages(
             agent_id=agent_id,
@@ -844,6 +845,11 @@ class SyncServer(object):
                 text_is_assistant_message=text_is_assistant_message,
             )
 
+            # Filter by message_types if specified
+            if message_types:
+                message_types_set = set(message_types)
+                records = [msg for msg in records if msg.message_type in message_types_set]
+
         if reverse:
             records = records[::-1]