Update main.py

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

main.py

@@ -81,7 +81,7 @@ async def root(
     # 如果没有指定日期范围，默认加载今天的日志
     if from_date is None and to_date is None:
         today = beijing().date().strftime("%Y-%m-%d")
-        from_date = today  # 最近30天（包括今天）
+        from_date = today  # 今天的日志
         to_date = today
         print(f"[root] No date range specified, using today: {from_date} to {to_date}")