修复txt导出不映射的问题

electron/services/exportService.ts

@@ -2546,12 +2546,15 @@ class ExportService {
 
       for (let i = 0; i < sortedMessages.length; i++) {
         const msg = sortedMessages[i]
-        const contentValue = this.formatPlainExportContent(
-          msg.content,
-          msg.localType,
-          options,
-          voiceTranscriptMap.get(msg.localId)
-        )
+        const mediaKey = `${msg.localType}_${msg.localId}`
+        const mediaItem = mediaCache.get(mediaKey)
+        const contentValue = mediaItem?.relativePath
+          || this.formatPlainExportContent(
+            msg.content,
+            msg.localType,
+            options,
+            voiceTranscriptMap.get(msg.localId)
+          )
 
         let senderRole: string
         let senderWxid: string