Fix method name: set_working_memory -> put_working_memory

The agent-memory-client API uses put_working_memory, not
set_working_memory. Updated memory_client.py to use the correct
method name.

Author: abrookins

python-recipes/context-engineering/reference-agent/redis_context_course/memory_client.py

@@ -137,8 +137,8 @@ async def save_working_memory(
             data=data or {},
             model_name=model_name
         )
-        
-        return await self.client.set_working_memory(working_memory)
+
+        return await self.client.put_working_memory(working_memory)
 
     async def add_message_to_working_memory(
         self,