feat: 更新考试相关页面，添加刷新功能，修改考试状态显示

- 注：当前代码还存在bug：查看结果暂出现错误。
- 在 SubjectSelectionPage 页面中添加刷新按钮，允许用户手动刷新考试任务列表。
- 修改 UserTaskPage 页面，重构考试任务为答题记录，更新数据结构和状态显示。
- 在 AdminDashboardPage、UserManagePage、UserRecordsPage 等管理页面中添加考试状态显示，使用不同颜色区分状态（不及格、合格、优秀）。
- 在 ResultPage 中显示考试状态，确保用户能够清晰了解考试结果。
- 添加约束，确保单次考试试卷中题目不可重复出现，并记录相关规范。
- 添加评分状态约束，根据得分占比自动计算考试状态，并在结果页面显示。

api/models/examSubject.ts

@@ -96,11 +96,10 @@ export class ExamSubjectModel {
 
         const targetTypeScore = Math.round((typeRatio / 100) * subject.totalScore);
         let currentTypeScore = 0;
-        let typeQuestions: Awaited<ReturnType<typeof QuestionModel.getRandomQuestions>> = [];
 
         while (currentTypeScore < targetTypeScore) {
           const randomCategory = weightedCategories[Math.floor(Math.random() * weightedCategories.length)];
-          const availableQuestions = await QuestionModel.getRandomQuestions(type as any, 10, [randomCategory]);
+          const availableQuestions = await QuestionModel.getRandomQuestions(type as any, 100, [randomCategory]);
 
           if (availableQuestions.length === 0) break;
 
@@ -114,13 +113,11 @@ export class ExamSubjectModel {
             return currDiff < prevDiff ? curr : prev;
           });
 
-          typeQuestions.push(selectedQuestion);
+          questions.push(selectedQuestion);
           currentTypeScore += selectedQuestion.score;
 
-          if (typeQuestions.length > 100) break;
+          if (questions.length > 200) break;
         }
-
-        questions.push(...typeQuestions);
       }
       let totalScore = questions.reduce((sum, q) => sum + q.score, 0);
       while (totalScore < subject.totalScore) {
@@ -128,7 +125,7 @@ export class ExamSubjectModel {
         if (allTypes.length === 0) break;
 
         const randomType = allTypes[Math.floor(Math.random() * allTypes.length)];
-        const availableQuestions = await QuestionModel.getRandomQuestions(randomType as any, 10, categories);
+        const availableQuestions = await QuestionModel.getRandomQuestions(randomType as any, 100, categories);
         if (availableQuestions.length === 0) break;
 
         const availableUnselected = availableQuestions.filter((q) => !questions.some((selected) => selected.id === q.id));
@@ -165,9 +162,13 @@ export class ExamSubjectModel {
         questions.splice(closestIndex, 1);
       }
 
+      const uniqueQuestions = questions.filter((q, index, self) => 
+        index === self.findIndex((t) => t.id === q.id)
+      );
+
       return {
-        questions,
-        totalScore,
+        questions: uniqueQuestions,
+        totalScore: uniqueQuestions.reduce((sum, q) => sum + q.score, 0),
         timeLimitMinutes: subject.timeLimitMinutes,
       };
     }
@@ -213,7 +214,7 @@ export class ExamSubjectModel {
           tried.add(category);
 
           const desiredAvg = remainingSlots > 0 ? (subject.totalScore - currentTotal) / remainingSlots : 0;
-          const fetched = await QuestionModel.getRandomQuestions(type as any, 30, [category]);
+          const fetched = await QuestionModel.getRandomQuestions(type as any, 100, [category]);
           const candidates = fetched.filter((q) => !questions.some((selectedQ) => selectedQ.id === q.id));
           if (candidates.length === 0) continue;
 
@@ -227,7 +228,7 @@ export class ExamSubjectModel {
         }
 
         if (!selected || !selectedCategory) {
-          throw new Error('题库中缺少满足当前配置的题目');
+          continue;
         }
 
         questions.push(selected);
@@ -245,8 +246,8 @@ export class ExamSubjectModel {
 
       const idx = Math.floor(Math.random() * questions.length);
       const base = questions[idx];
-      const fetched = await QuestionModel.getRandomQuestions(base.type as any, 30, [base.category]);
-      const candidates = fetched.filter((q) => !questions.some((selectedQ) => selectedQ.id === q.id));
+      const fetched = await QuestionModel.getRandomQuestions(base.type as any, 100, [base.category]);
+      const candidates = fetched.filter((q) => !questions.some((selectedQ) => selectedQ.id === q.id) && q.id !== base.id);
       if (candidates.length === 0) continue;
 
       const currentBest = Math.abs(diff);
@@ -267,9 +268,13 @@ export class ExamSubjectModel {
       totalScore = totalScore - base.score + best.score;
     }
 
+    const uniqueQuestions = questions.filter((q, index, self) => 
+      index === self.findIndex((t) => t.id === q.id)
+    );
+
     return {
-      questions,
-      totalScore,
+      questions: uniqueQuestions,
+      totalScore: uniqueQuestions.reduce((sum, q) => sum + q.score, 0),
       timeLimitMinutes: subject.timeLimitMinutes,
     };
   }