fix: deserialize LangChain messages in async checkpoint operations (#87)

Add _recursive_deserialize to AsyncRedisSaver.aget_tuple() and alist() methods to properly deserialize LangChain messages from their stored format, matching the sync implementation behavior.

Author: aarongrtech

langgraph/checkpoint/redis/aio.py

@@ -540,13 +540,13 @@ async def aget_tuple(self, config: RunnableConfig) -> Optional[CheckpointTuple]:
         # Execute all tasks in parallel - pending_sends is optional
         if doc_parent_checkpoint_id:
             results = await asyncio.gather(*tasks)
-            channel_values: Dict[str, Any] = results[0]
+            channel_values: Dict[str, Any] = self._recursive_deserialize(results[0])
             pending_sends: List[Tuple[str, Union[str, bytes]]] = results[1]
             pending_writes: List[PendingWrite] = results[2]
         else:
             # Only channel_values and pending_writes tasks
             results = await asyncio.gather(*tasks)
-            channel_values = results[0]
+            channel_values = self._recursive_deserialize(results[0])
             pending_sends = []
             pending_writes = results[1]
 
@@ -709,7 +709,7 @@ async def alist(
                     if isinstance(checkpoint_data, dict)
                     else orjson.loads(checkpoint_data)
                 )
-                channel_values = checkpoint_dict.get("channel_values", {})
+                channel_values = self._recursive_deserialize(checkpoint_dict.get("channel_values", {}))
             else:
                 # If checkpoint data is missing, the document is corrupted
                 # Set empty channel values rather than attempting a fallback