Phase 1+2 구현: Electron 뼈대 + STT/핫키/오케스트레이터

Phase 1:
- 프로젝트 초기화 (TypeScript strict, electron-vite, ESLint, Prettier)
- shared 타입 (ipc-channels 113채널, types, errors, constants)
- 메인 프로세스 뼈대 (bootstrap, lifecycle, 단일 인스턴스)
- LoggerService, ConfigService (electron-store ESM dynamic import)
- React 19 + MUI 7 Dashboard, 시스템 트레이

Phase 2:
- AudioCaptureService (node-record-lpcm16, PCM16 16kHz mono)
- HotkeyService (uiohook-napi, 더블프레스, holdMode/toggleMode)
- LocalSTTService (faster-whisper Python sidecar, 이중 조건 플러시)
- VoiceModeService 오케스트레이터 (이중 상태머신, Action Queue)
- Python sidecar (FastAPI: health/load/transcribe/shutdown)
- IPC 핸들러 (voice, stt, hotkey) + Preload API 확장

src/main/ipc/stt-handlers.ts

@@ -0,0 +1,52 @@
+// src/main/ipc/stt-handlers.ts
+
+import { ipcMain } from 'electron'
+import { IPC_CHANNELS } from '@shared/ipc-channels'
+import { ipcSuccess, ipcError, ErrorCode } from '@shared/errors'
+import { getLocalSTTService } from '../services/LocalSTTService'
+import { configGet, configSet } from '../services/ConfigService'
+import type { SetSTTModelParams, SetSTTLanguageParams } from '@shared/types'
+
+export function registerSTTHandlers(): void {
+  ipcMain.handle(IPC_CHANNELS.STT.GET_STATUS, async () => {
+    try {
+      const stt = getLocalSTTService()
+      return ipcSuccess(stt.getStatus())
+    } catch {
+      return ipcError(ErrorCode.STTSidecarCommunicationFailed, 'Failed to get STT status')
+    }
+  })
+
+  ipcMain.handle(IPC_CHANNELS.STT.GET_MODELS, async () => {
+    try {
+      const stt = getLocalSTTService()
+      return ipcSuccess(await stt.getModels())
+    } catch {
+      return ipcError(ErrorCode.STTModelNotFound, 'Failed to get models')
+    }
+  })
+
+  ipcMain.handle(IPC_CHANNELS.STT.GET_ACTIVE_MODEL, async () => {
+    return ipcSuccess(configGet('sttModelId'))
+  })
+
+  ipcMain.handle(IPC_CHANNELS.STT.SET_MODEL, async (_event, params: SetSTTModelParams) => {
+    try {
+      configSet('sttModelId', params.modelId)
+      const stt = getLocalSTTService()
+      await stt.initialize(params.modelId)
+      return ipcSuccess(undefined)
+    } catch {
+      return ipcError(ErrorCode.STTModelLoadFailed, 'Failed to set STT model')
+    }
+  })
+
+  ipcMain.handle(IPC_CHANNELS.STT.GET_LANGUAGE, async () => {
+    return ipcSuccess(configGet('sttLanguage'))
+  })
+
+  ipcMain.handle(IPC_CHANNELS.STT.SET_LANGUAGE, async (_event, params: SetSTTLanguageParams) => {
+    configSet('sttLanguage', params.language)
+    return ipcSuccess(undefined)
+  })
+}