Update logging_helper.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

logging_helper.py

@@ -358,8 +358,10 @@ class LoggingHelper:
         print(f"[refresh] Filtering logs from {from_date} to {to_date}")
         # 创建日期范围过滤条件
         filter_condition = pd.Series([True] * len(df), index=df.index)
-        filter_condition = filter_condition & (df["timestamp"] >= from_date)
-        filter_condition = filter_condition & (df["timestamp"] < to_date)
+        if from_timestamp is not None:
+            filter_condition = filter_condition & (df["timestamp"] >= from_timestamp)
+        if to_timestamp is not None:
+            filter_condition = filter_condition & (df["timestamp"] < to_timestamp)
         df = df[filter_condition]
         # 按timestamp降序排序（最新日志在前）
         df = df.sort_values(by="timestamp", ascending=False)