问题卷标记，确保有任务

src/features/mark/MarkProblemDialog.vue

@@ -63,6 +63,10 @@ export default defineComponent({
     }
 
     const chooseProblemType = async (problemId: number) => {
+      if (!store.currentTask) {
+        message.warn({ content: "没有可以标记的任务", duration: 5 });
+        return;
+      }
       const res = await doProblemType(problemId);
       if (res.data.success) {
         message.success({ content: "问题卷处理成功", duration: 3 });