Merge pull request #82 from 5xiao0qing5/dev

实现 TXT导出 和 HTML导出

src/types/electron.d.ts

@@ -352,6 +352,7 @@ export interface ExportOptions {
   exportEmojis?: boolean
   exportVoiceAsText?: boolean
   excelCompactColumns?: boolean
+  txtColumns?: string[]
   sessionLayout?: 'shared' | 'per-session'
 }