fix: 被禁言导致发送线程死掉，修复所有的压缩，修复空日程的key error

src/plugins/schedule/schedule_generator.py

@@ -104,6 +104,8 @@ class ScheduleGenerator:
         min_diff = float('inf')
         
         # 检查今天的日程
+        if not self.today_schedule.keys():
+            return "摸鱼"
         for time_str in self.today_schedule.keys():
             diff = abs(self._time_diff(current_time, time_str))
             if closest_time is None or diff < min_diff: