fix: update memory get

Author: fridayL

src/memos/reranker/concat.py

@@ -1,4 +1,7 @@
 from typing import Any
+import re
+
+_TAG1 = re.compile(r"^\s*\[[^\]]*\]\s*")
 
 
 def process_source(
@@ -39,7 +42,7 @@ def concat_original_source(
         merge_field = ["sources"]
     documents = []
     for item in graph_results:
-        memory = getattr(item, "memory", "")
+        memory = (_TAG1.sub("", m) if isinstance((m := getattr(item, "memory", None)), str) else m)
         sources = []
         for field in merge_field:
             source = getattr(item.metadata, field, "")