fix: rubric:storeData 空数据保护防止误清

electron/main/ipc.ts

@@ -254,9 +254,14 @@ export function setupIpc(win: BrowserWindow): void {
   // --- Rubric data bridge (toolbar ↔ rubric window), persisted to DB ---
   ipcMain.handle('rubric:storeData', (_event, data: any) => {
     const d = getDb()
+    const questions = data?.questions || []
+    // Don't clear rubric data when saving empty data (preserve existing)
+    if (questions.length === 0) {
+      rubricPayload = data
+      return
+    }
     d.prepare('DELETE FROM rubric').run()
     const insert = d.prepare('INSERT INTO rubric (question_title, max_score, reference_answer, rubric, sort_order) VALUES (?, ?, ?, ?, ?)')
-    const questions = data?.questions || []
     for (let i = 0; i < questions.length; i++) {
       const q = questions[i]
       insert.run(q.questionTitle || '', q.maxScore ?? 100, q.referenceAnswer || '', q.rubric || '', i)
@@ -300,7 +305,7 @@ async function callAiApi(imageBase64: string, rubric: string, config: { apiKey:
   deductions: string[]
   comment: string
 }> {
-  const systemRole = `你是高校阅卷专家，严格按照评分标准逐项评分。`
+  const systemRole = `你是高校阅卷专家，严格按照评分标准逐项评分。只输出JSON，不包含任何其他文字。`
 
   const prompt = `${extras?.questionTitle ? `【题目】\n${extras.questionTitle}\n` : ''}【评分标准】
 ${rubric || '无'}
@@ -322,7 +327,8 @@ ${extras?.maxScore ?? 100}
 3. 如果学生答案为空、空白或明显与题目无关，直接给0分
 4. 部分正确时按评分标准酌情给分
 
-请严格按照以下JSON格式返回结果，不要包含任何markdown标记或其他文字：
+【输出要求】
+只输出以下JSON，不要包含markdown代码块、\`\`\`标记、注释或任何其他文字：
 {
   "score": <总分>,
   "confidence": <置信度0~1>,