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/preload/index.ts

@@ -35,6 +35,8 @@ import type {
   SetSTTModelParams,
   SetSTTLanguageParams,
   STTStatusChangedEvent,
+  DownloadModelParams,
+  DownloadProgressEvent,
   HotkeyBinding,
   SetHotkeyParams,
   SetEnabledParams,
@@ -251,11 +253,16 @@ const electronAPI = {
     getActiveModel: () => invoke<string | null>(IPC_CHANNELS.STT.GET_ACTIVE_MODEL),
     setModel: (params: SetSTTModelParams) =>
       invoke<void>(IPC_CHANNELS.STT.SET_MODEL, params),
+    downloadModel: (params: DownloadModelParams) =>
+      invoke<void>(IPC_CHANNELS.STT.DOWNLOAD_MODEL, params),
+    cancelDownload: () => invoke<void>(IPC_CHANNELS.STT.CANCEL_DOWNLOAD),
     getLanguage: () => invoke<string>(IPC_CHANNELS.STT.GET_LANGUAGE),
     setLanguage: (params: SetSTTLanguageParams) =>
       invoke<void>(IPC_CHANNELS.STT.SET_LANGUAGE, params),
     onStatusChanged: (cb: (e: STTStatusChangedEvent) => void): Unsubscribe =>
-      on(IPC_CHANNELS.STT.STATUS_CHANGED, cb)
+      on(IPC_CHANNELS.STT.STATUS_CHANGED, cb),
+    onDownloadProgress: (cb: (e: DownloadProgressEvent) => void): Unsubscribe =>
+      on(IPC_CHANNELS.STT.DOWNLOAD_PROGRESS, cb)
   },
 
   // ── Hotkey ─────────────────────────────────────────────