fix: 上一题/下一题不再调 AI API，改为保存后关闭并推进索引

electron/main/ipc.ts

@@ -314,6 +314,12 @@ export function setupIpc(win: BrowserWindow): void {
     return { questions, currentIndex: 0 }
   })
 
+  // --- Rubric next question index (persisted between grading cycles) ---
+  let rubricNextIndex = 0
+  ipcMain.handle('rubric:getNextIndex', () => rubricNextIndex)
+  ipcMain.handle('rubric:setNextIndex', (_event, idx: number) => { rubricNextIndex = idx })
+  ipcMain.handle('rubric:resetNextIndex', () => { rubricNextIndex = 0 })
+
   // --- Grading data bridge (toolbar → result window) ---
   ipcMain.handle('grading:storeData', (_event, data: any) => {
     gradingPayload = data

electron/preload/preload.ts

@@ -52,7 +52,10 @@ contextBridge.exposeInMainWorld('electronAPI', {
     storeData: (data: any) => ipcRenderer.invoke('rubric:storeData', data),
     getData: () => ipcRenderer.invoke('rubric:getData'),
     exportJson: () => ipcRenderer.invoke('rubric:exportJson'),
-    importJson: () => ipcRenderer.invoke('rubric:importJson')
+    importJson: () => ipcRenderer.invoke('rubric:importJson'),
+    getNextIndex: () => ipcRenderer.invoke('rubric:getNextIndex'),
+    setNextIndex: (idx: number) => ipcRenderer.invoke('rubric:setNextIndex', idx),
+    resetNextIndex: () => ipcRenderer.invoke('rubric:resetNextIndex')
   },
 
   template: {