fix: 评分标准直读 DB，移除缓存层

electron/main/ipc.ts

@@ -262,11 +262,9 @@ export function setupIpc(win: BrowserWindow): void {
       const q = questions[i]
       insert.run(q.questionTitle || '', q.maxScore ?? 100, q.referenceAnswer || '', q.rubric || '', i)
     }
-    rubricPayload = data
   })
 
   ipcMain.handle('rubric:getData', () => {
-    function fromDb() {
     const d = getDb()
     const rows: any[] = d.prepare('SELECT * FROM rubric ORDER BY sort_order').all()
     if (rows.length) {
@@ -281,14 +279,6 @@ export function setupIpc(win: BrowserWindow): void {
       }
     }
     return null
-    }
-    if (rubricPayload && rubricPayload.questions?.length) return rubricPayload
-    const dbResult = fromDb()
-    if (dbResult) {
-      rubricPayload = dbResult
-      return dbResult
-    }
-    return null
   })
 
   // --- Grading data bridge (toolbar → result window) ---
@@ -300,7 +290,6 @@ export function setupIpc(win: BrowserWindow): void {
 }
 
 const dialogPayloads: Record<string, any> = {}
-let rubricPayload: any = null
 let gradingPayload: any = null
 
 async function callAiApi(imageBase64: string, rubric: string, config: { apiKey: string; baseUrl: string; model: string }, extras?: { maxScore?: number; referenceAnswer?: string; questionTitle?: string }): Promise<{