fixed cheating michanism

server/models/Vocabulary.ts

@@ -65,6 +65,31 @@ export interface IVocabularyTestAttempt extends Document {
   testType: 'chinese-to-english' | 'audio-to-english' | 'multiple-choice';
   questionWordIds: mongoose.Types.ObjectId[];
   questionTokens: string[];
+  optionTokens?: string[][];
+  optionTexts?: string[][];
+  answeredQuestionTokens?: string[];
+  answerDurations?: number[];
+  answers?: Array<{
+    questionToken: string;
+    word: mongoose.Types.ObjectId;
+    userAnswer: string;
+    correctAnswer: string;
+    isCorrect: boolean;
+    submittedAt: Date;
+    duration: number;
+    riskFlags: string[];
+    interactionSummary?: {
+      keyCount: number;
+      inputCount: number;
+      pasteCount: number;
+      focusCount: number;
+      blurCount: number;
+      pointerCount: number;
+      firstEventOffset: number;
+      lastEventOffset: number;
+    };
+  }>;
+  riskFlags?: string[];
   issuedAt: Date;
   expiresAt: Date;
   submittedAt?: Date;
@@ -163,6 +188,31 @@ const VocabularyTestAttemptSchema = new Schema<IVocabularyTestAttempt>({
   },
   questionWordIds: [{ type: Schema.Types.ObjectId, ref: 'Word', required: true }],
   questionTokens: [{ type: String, required: true }],
+  optionTokens: [[{ type: String }]],
+  optionTexts: [[{ type: String }]],
+  answeredQuestionTokens: [{ type: String }],
+  answerDurations: [{ type: Number }],
+  answers: [{
+    questionToken: { type: String, required: true },
+    word: { type: Schema.Types.ObjectId, ref: 'Word', required: true },
+    userAnswer: { type: String, default: '' },
+    correctAnswer: { type: String, required: true },
+    isCorrect: { type: Boolean, required: true },
+    submittedAt: { type: Date, required: true },
+    duration: { type: Number, required: true },
+    riskFlags: [{ type: String }],
+    interactionSummary: {
+      keyCount: { type: Number, default: 0 },
+      inputCount: { type: Number, default: 0 },
+      pasteCount: { type: Number, default: 0 },
+      focusCount: { type: Number, default: 0 },
+      blurCount: { type: Number, default: 0 },
+      pointerCount: { type: Number, default: 0 },
+      firstEventOffset: { type: Number, default: 0 },
+      lastEventOffset: { type: Number, default: 0 }
+    }
+  }],
+  riskFlags: [{ type: String }],
   issuedAt: { type: Date, required: true },
   expiresAt: { type: Date, required: true },
   submittedAt: Date,