feat: end-to-end choice question support in assessment pipeline

- Data pathway: flow options through questions, answerKey in graph state
- Interviewer: format MULTIPLE_CHOICE with A/B/C/D options
- Grader: instant choice scoring (zero LLM), compare correctAnswer
- AssessmentView: render choice buttons vs textarea based on questionType
- Security: sanitizeStateForClient strips correctAnswer/judgment/answerKey
- Bank detection: check PUBLISHED items (not PUBLISHED bank status)
- Batch UI: select all / batch approve / batch reject on detail view

server/src/assessment/graph/nodes/grader.node.ts

@@ -67,6 +67,31 @@ export const graderNode = async (
     return { currentQuestionIndex: currentQuestionIndex + 1 };
   }
 
+  const isChoice = currentQuestion.questionType === 'MULTIPLE_CHOICE';
+  const answerKey = (state.questionAnswerKey as any)?.[currentQuestion.id];
+
+  if (isChoice || answerKey?.correctAnswer) {
+    const expectedAnswer = answerKey?.correctAnswer || currentQuestion.correctAnswer;
+    const userAnswer = (lastUserMessage.content as string).trim();
+    const isCorrect = userAnswer.toUpperCase() === expectedAnswer?.toUpperCase();
+
+    console.log('[GraderNode] Choice grading:', { userAnswer, expectedAnswer, isCorrect });
+
+    const feedback = isCorrect ? '✅ 正确' : `❌ 错误，正确答案是 ${expectedAnswer}`;
+    const feedbackMessage = new AIMessage(
+      { content: `Score: ${isCorrect ? 10 : 0}\nFeedback: ${feedback}` } as any,
+    );
+
+    return {
+      messages: [feedbackMessage],
+      feedbackHistory: [feedbackMessage],
+      scores: { [currentQuestion.id || currentQuestionIndex.toString()]: isCorrect ? 10 : 0 },
+      shouldFollowUp: false,
+      followUpCount: 0,
+      currentQuestionIndex: currentQuestionIndex + 1,
+    };
+  }
+
   const systemPromptZh = `你是一位专业的考官。
 请根据以下问题和关键点对用户的回答进行评分。