feat(bootstrap): Whisper large-v3-turbo 기본 전환 + 온보딩 2단계 다운로드 진행률

- 기본 STT 모델 base → large-v3-turbo (6배 빠름, 1.6GB)
- 사이드카: /download, /download/status, /download/cancel + --models-dir
- LocalSTTService: downloadModel/cancelDownload + download-progress 이벤트
- IPC: 설계서 02의 stt:downloadModel/cancelDownload/downloadProgress 구현
- OnboardingModal: LLM(gemma4:e4b) → STT(turbo) 2단계 순차 다운로드 UI
- SettingsModal turbo 선택지 + settings.model.largeTurbo 12 locale
- 테스트: 모노레포 잔재 import 수정 (src/shared → @d3ro/core), 41/41 통과

apps/desktop/src/renderer/components/SettingsModal.tsx

@@ -629,6 +629,7 @@ export function SettingsModal({ open, onClose }: SettingsModalProps): React.Reac
                   <MenuItem value="small">{t('settings.model.small')}</MenuItem>
                   <MenuItem value="medium">{t('settings.model.medium')}</MenuItem>
                   <MenuItem value="large-v3">{t('settings.model.large')}</MenuItem>
+                  <MenuItem value="large-v3-turbo">{t('settings.model.largeTurbo')}</MenuItem>
                 </Select>
               </FormControl>