- RecorderState.isFinalizing flag set during stopRecording → finishWriting
- applicationShouldTerminate returns .terminateLater if finalizing
- Shows alert '正在保存录制文件...' to inform user
- After save dialog completes, calls NSApp.reply(toApplicationShouldTerminate: true)
- All failure paths also check and resolve pendingTerminate
- Fixes: 9-min recording lost because user closed app before async finishWriting completed