feat: add topk for working mem (#476)

Author: fridayL

src/memos/memories/textual/tree_text_memory/retrieve/recall.py

@@ -66,7 +66,7 @@ def retrieve(
             working_memories = self.graph_store.get_all_memory_items(
                 scope="WorkingMemory", include_embedding=False, user_name=user_name
             )
-            return [TextualMemoryItem.from_dict(record) for record in working_memories]
+            return [TextualMemoryItem.from_dict(record) for record in working_memories[:top_k]]
 
         with ContextThreadPoolExecutor(max_workers=3) as executor:
             # Structured graph-based retrieval

src/memos/memories/textual/tree_text_memory/retrieve/searcher.py

@@ -108,7 +108,7 @@ def post_retrieve(
     def search(
         self,
         query: str,
-        top_k: int,
+        top_k: int = 10,
         info=None,
         mode="fast",
         memory_type="All",