feat(V2-1a): Monorepo 구조 전환 — apps/desktop으로 V1 이동

- npm workspaces 루트 (apps/*, packages/*) 세팅
- V1 전체를 apps/desktop/으로 git mv (src, resources, tests, sidecar,
  scripts, electron.vite.config.ts, electron-builder.yml, vitest.config.ts,
  tsconfig.node.json, tsconfig.web.json)
- apps/desktop/package.json 신규 (name=@d3ro/desktop)
- productName: 'd3ro-voice' 명시 — app.getName()을 고정하여 userData 경로
  %APPDATA%\d3ro-voice\ 그대로 유지 (기존 DB/설정 연속성 보장)
- 루트 package.json을 workspace 루트로 재구성, 공통 devDep만 유지
  (typescript, eslint, prettier)
- turbo.json, tsconfig.base.json 추가 (Turborepo 자체 설치는 별도 sub-phase)
- memory/project_status.md 생성 (규칙 13)

검증:
- npm run typecheck 통과
- npm run build 통과 (electron-vite main+preload+renderer)
- npm run dev 실제 실행 → DB/핫키/Ollama 자동 실행 모두 정상

apps/desktop/src/main/ipc/caption-handlers.ts

@@ -0,0 +1,69 @@
+// src/main/ipc/caption-handlers.ts
+// Phase 10.1: Live Caption IPC 핸들러
+
+import { ipcMain, session, desktopCapturer } from 'electron'
+import { IPC_CHANNELS } from '@shared/ipc-channels'
+import { ipcSuccess, ipcError, ErrorCode } from '@shared/errors'
+import { getCaptionService } from '../services/CaptionService'
+import type { CaptionConfig } from '@shared/types'
+
+export function registerCaptionHandlers(): void {
+  // 시스템 오디오 루프백: setDisplayMediaRequestHandler로 audio: 'loopback' 설정
+  ipcMain.handle('system-audio:enable-loopback', async () => {
+    session.defaultSession.setDisplayMediaRequestHandler(async (_request, callback) => {
+      const sources = await desktopCapturer.getSources({ types: ['screen'] })
+      if (sources.length === 0) {
+        callback({})
+        return
+      }
+      callback({ video: sources[0], audio: 'loopback' })
+    })
+    return ipcSuccess(undefined)
+  })
+
+  ipcMain.handle('system-audio:disable-loopback', async () => {
+    session.defaultSession.setDisplayMediaRequestHandler(null)
+    return ipcSuccess(undefined)
+  })
+  ipcMain.handle(IPC_CHANNELS.CAPTION.START, async () => {
+    try {
+      await getCaptionService().start()
+      return ipcSuccess(undefined)
+    } catch (err) {
+      const code =
+        err instanceof Error && 'code' in err
+          ? (err as { code: number }).code
+          : ErrorCode.CaptionStartFailed
+      const message = err instanceof Error ? err.message : String(err)
+      return ipcError(code, message)
+    }
+  })
+
+  ipcMain.handle(IPC_CHANNELS.CAPTION.STOP, async () => {
+    try {
+      await getCaptionService().stop()
+      return ipcSuccess(undefined)
+    } catch (err) {
+      const message = err instanceof Error ? err.message : String(err)
+      return ipcError(ErrorCode.CaptionStartFailed, message)
+    }
+  })
+
+  ipcMain.handle(IPC_CHANNELS.CAPTION.GET_STATE, async () => {
+    return ipcSuccess(getCaptionService().getState())
+  })
+
+  ipcMain.handle(IPC_CHANNELS.CAPTION.SET_CONFIG, async (_event, config: Partial<CaptionConfig>) => {
+    getCaptionService().setConfig(config)
+    return ipcSuccess(undefined)
+  })
+
+  ipcMain.handle(IPC_CHANNELS.CAPTION.GET_CONFIG, async () => {
+    return ipcSuccess(getCaptionService().getConfig())
+  })
+
+  // 렌더러 → 메인: 시스템 오디오 PCM 데이터 수신
+  ipcMain.on(IPC_CHANNELS.CAPTION.SYSTEM_AUDIO_DATA, (_event, data: ArrayBuffer) => {
+    getCaptionService().onSystemAudioData(Buffer.from(data))
+  })
+}