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/ReviewDetail.vue

@@ -295,7 +295,7 @@ watch(
         />
         <div class="edit-actions">
           <el-button @click="cancelEdit">取消</el-button>
-          <el-button type="primary" :loading="saving" @click="saveEdit">保存</el-button>
+          <el-button type="success" :loading="saving" @click="saveEdit">保存</el-button>
         </div>
       </div>
       <!-- 只读模式 -->
@@ -328,7 +328,7 @@ watch(
             >
               <el-button type="success" :loading="mindMapUploading">上传导图文件</el-button>
             </el-upload>
-            <el-button type="primary" size="small" @click="router.push(`/review/recall/${taskNum}`)">
+            <el-button type="success" size="small" @click="router.push(`/review/recall/${taskNum}`)">
               回忆复习
             </el-button>
             <el-tag v-if="mindMap?.fileFormat" size="small" effect="plain">