fix: natural follow-up conversation flow

- Grader: separate followup hint from scoring feedback
- Interviewer: use followup hint directly without prefix/suffix
- Restored standard and choice question presentation paths

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

@@ -49,27 +49,7 @@ export const interviewerNode = async (
   ) {
     const lastFeedbackMsg =
       state.feedbackHistory[state.feedbackHistory.length - 1];
-    const feedbackText = lastFeedbackMsg.content.toString();
-
-    const feedbackMatch = feedbackText.match(
-      /(?:Feedback|反馈|フィードバック): ([\s\S]*)/i,
-    );
-    const specificFeedback = feedbackMatch
-      ? feedbackMatch[1].trim()
-      : feedbackText;
-
-    const followUpLabel = isZh
-      ? '补充追问'
-      : isJa
-        ? '追加の質問'
-        : 'Follow-up Clarification';
-    const followUpInstruction = isZh
-      ? '根据以上反馈，请补充更具体的信息：'
-      : isJa
-        ? '上記のフィードバックに基づき、より具体的な情報を追加してください：'
-        : 'Based on the feedback above, please provide more specific details:';
-
-    prompt = `${followUpLabel}\n\n${specificFeedback}\n\n${followUpInstruction}`;
+    prompt = lastFeedbackMsg.content.toString();
   } else if (currentQuestion.questionType === 'MULTIPLE_CHOICE' && currentQuestion.options?.length > 0) {
     const label = isZh
       ? `问题 ${currentQuestionIndex + 1}`