fix: 修复答题界面抽屉点击已答题目时答案丢失的问题

- 添加 userAnswers 和 questionResults 状态，存储每道题的答案和结果
- 在 handleSubmit 中保存用户答案和答题结果到 Map
- 在 handleQuestionSelect 中恢复之前的答案和结果
- 更新 saveProgress 和 loadProgress，支持持久化用户答案和结果
- 现在点击抽屉中已答题目会正确显示之前的答案和结果

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

web/src/pages/Question.tsx

@@ -33,6 +33,10 @@ const QuestionPage: React.FC = () => {
   const [drawerVisible, setDrawerVisible] = useState(false);
   const [answeredStatus, setAnsweredStatus] = useState<Map<number, boolean | null>>(new Map());
 
+  // 存储每道题的用户答案和答题结果
+  const [userAnswers, setUserAnswers] = useState<Map<number, string | string[]>>(new Map());
+  const [questionResults, setQuestionResults] = useState<Map<number, AnswerResult>>(new Map());
+
   // 设置弹窗
   const [settingsVisible, setSettingsVisible] = useState(false);
 
@@ -87,6 +91,8 @@ const QuestionPage: React.FC = () => {
   const saveProgress = (index: number, correct: number, wrong: number, statusMap?: Map<number, boolean | null>) => {
     const key = getStorageKey();
     const answeredStatusObj: Record<number, boolean | null> = {};
+    const userAnswersObj: Record<number, string | string[]> = {};
+    const questionResultsObj: Record<number, AnswerResult> = {};
 
     // 将 Map 转换为普通对象以便 JSON 序列化
     const mapToSave = statusMap || answeredStatus;
@@ -94,6 +100,14 @@ const QuestionPage: React.FC = () => {
       answeredStatusObj[key] = value;
     });
 
+    userAnswers.forEach((value, key) => {
+      userAnswersObj[key] = value;
+    });
+
+    questionResults.forEach((value, key) => {
+      questionResultsObj[key] = value;
+    });
+
     localStorage.setItem(
       key,
       JSON.stringify({
@@ -101,6 +115,8 @@ const QuestionPage: React.FC = () => {
         correctCount: correct,
         wrongCount: wrong,
         answeredStatus: answeredStatusObj,
+        userAnswers: userAnswersObj,
+        questionResults: questionResultsObj,
         timestamp: Date.now(),
       })
     );
@@ -126,6 +142,24 @@ const QuestionPage: React.FC = () => {
           setAnsweredStatus(statusMap);
         }
 
+        // 恢复用户答案
+        if (progress.userAnswers) {
+          const answersMap = new Map<number, string | string[]>();
+          Object.entries(progress.userAnswers).forEach(([index, answer]) => {
+            answersMap.set(Number(index), answer as string | string[]);
+          });
+          setUserAnswers(answersMap);
+        }
+
+        // 恢复答题结果
+        if (progress.questionResults) {
+          const resultsMap = new Map<number, AnswerResult>();
+          Object.entries(progress.questionResults).forEach(([index, result]) => {
+            resultsMap.set(Number(index), result as AnswerResult);
+          });
+          setQuestionResults(resultsMap);
+        }
+
         return progress.currentIndex || 0;
       } catch (e) {
         console.error("恢复进度失败", e);
@@ -252,6 +286,15 @@ const QuestionPage: React.FC = () => {
         setAnswerResult(res.data);
         setShowResult(true);
 
+        // 保存用户答案和结果到 Map
+        const newAnswersMap = new Map(userAnswers);
+        newAnswersMap.set(currentIndex, selectedAnswer);
+        setUserAnswers(newAnswersMap);
+
+        const newResultsMap = new Map(questionResults);
+        newResultsMap.set(currentIndex, res.data);
+        setQuestionResults(newResultsMap);
+
         // 更新答题状态
         const newStatusMap = new Map(answeredStatus);
         newStatusMap.set(currentIndex, res.data.correct);
@@ -356,11 +399,24 @@ const QuestionPage: React.FC = () => {
     if (index >= 0 && index < allQuestions.length) {
       setCurrentIndex(index);
       setCurrentQuestion(allQuestions[index]);
-      setSelectedAnswer(
-        allQuestions[index].type === "multiple-selection" ? [] : ""
-      );
-      setShowResult(false);
-      setAnswerResult(null);
+
+      // 检查是否有保存的答案和结果
+      const savedAnswer = userAnswers.get(index);
+      const savedResult = questionResults.get(index);
+
+      if (savedAnswer !== undefined && savedResult !== undefined) {
+        // 恢复之前的答案和结果
+        setSelectedAnswer(savedAnswer);
+        setAnswerResult(savedResult);
+        setShowResult(true);
+      } else {
+        // 没有答案，重置状态
+        setSelectedAnswer(
+          allQuestions[index].type === "multiple-selection" ? [] : ""
+        );
+        setShowResult(false);
+        setAnswerResult(null);
+      }
 
       // 保存进度
       saveProgress(index, correctCount, wrongCount);