fix(番茄钟)：进度环与倒计时方向一致

commit 9c2c1b7 错误地将 progress 改为 (total-current)/total，
导致数字递减但进度环递增（从空到满）。实际 runCountdown
中 timerMinutes/timerSeconds 存储的是剩余时间，应直接用
remaining/total 使环从 100%→0% 递减。

src/components/StartTask.vue

@@ -81,8 +81,8 @@ const breakAudio = new Audio('/resource/notification.mp3');
 
 const progress = computed(() => {
   const total = isBreak.value ? 5 * 60 : 25 * 60;
-  const current = timerMinutes.value * 60 + timerSeconds.value;
-  return ((total - current) / total) * 100;
+  const remaining = timerMinutes.value * 60 + timerSeconds.value;
+  return (remaining / total) * 100;
 });
 const nowTimestamp = ref(Date.now());