fix(前端)：进度环方向 + 按钮颜色 + 删除确认 + 移除 console.log

- StartTask.vue：progress 计算改为 (total-current)/total*100，进度环从
  满到空递减（正确方向）
- ReviewDetail/ReviewRecall/MindMapViewer：type="primary" 全部改为
  type="success"，统一绿白主题
- Study.vue：删除任务增加 ElMessageBox.confirm 确认
- request.ts：移除全部 console.log

src/components/StartTask.vue

@@ -81,7 +81,8 @@ const breakAudio = new Audio('/resource/notification.mp3');
 
 const progress = computed(() => {
   const total = isBreak.value ? 5 * 60 : 25 * 60;
-  return ((timerMinutes.value * 60 + timerSeconds.value) / total) * 100;
+  const current = timerMinutes.value * 60 + timerSeconds.value;
+  return ((total - current) / total) * 100;
 });
 const nowTimestamp = ref(Date.now());