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/services/VoiceConversationService.ts

@@ -0,0 +1,376 @@
+// src/main/services/VoiceConversationService.ts
+// Phase 13.1: 음성 대화 모드 — STT → LLM(chat) → TTS 루프
+// 싱글톤 + EventEmitter. 대화 히스토리 최근 10턴 유지.
+
+import { EventEmitter } from 'events'
+import { nanoid } from 'nanoid'
+import { getLogger } from './LoggerService'
+import { getLocalLLMService } from './LocalLLMService'
+import { getLocalSTTService } from './LocalSTTService'
+import { getAudioCaptureService } from './AudioCaptureService'
+import { getTTSPlaybackService } from './TTSPlaybackService'
+import { configGet } from './ConfigService'
+import { getMainWindow } from '../windows/WindowManager'
+import { IPC_CHANNELS } from '@shared/ipc-channels'
+import { D3ROError, ErrorCode } from '@shared/errors'
+import type {
+  ConversationState,
+  ConversationMessage,
+  ConversationSessionInfo,
+  ConversationAssistantDelta,
+  ConversationAssistantMessage,
+  ConversationError,
+} from '@shared/types'
+
+const logger = getLogger('VoiceConversationService')
+
+/** 대화 히스토리 최대 턴 수 (user+assistant 쌍) */
+const MAX_HISTORY_TURNS = 10
+/** 시스템 프롬프트 */
+const SYSTEM_PROMPT = `You are D3RO, a helpful local AI voice assistant. Respond concisely and naturally, as if having a spoken conversation. Keep answers brief (2-3 sentences) unless the user asks for detail. Respond in the same language the user speaks.`
+
+class VoiceConversationService extends EventEmitter {
+  private _state: ConversationState = 'idle'
+  private _messages: ConversationMessage[] = []
+  private _isActive = false
+  private _audioBuffers: Buffer[] = []
+  private _audioListenerBound = false
+
+  get state(): ConversationState {
+    return this._state
+  }
+
+  get isActive(): boolean {
+    return this._isActive
+  }
+
+  getSessionInfo(): ConversationSessionInfo {
+    return {
+      state: this._state,
+      messages: [...this._messages],
+      isActive: this._isActive,
+    }
+  }
+
+  getHistory(): ConversationMessage[] {
+    return [...this._messages]
+  }
+
+  /**
+   * 대화 세션 시작. 마이크 캡처를 시작하고 listening 상태로 진입.
+   */
+  async startSession(): Promise<void> {
+    if (this._isActive) {
+      throw new D3ROError(ErrorCode.ConversationSessionAlreadyActive, 'Conversation session already active')
+    }
+
+    // 라이센스 체크
+    try {
+      const { getLicenseService } = await import('./LicenseService')
+      const { Feature } = await import('@shared/types')
+      const license = getLicenseService()
+      const access = license.canUse(Feature.VOICE_CONVERSATION)
+      if (!access.allowed) {
+        license.promptUpgrade(Feature.VOICE_CONVERSATION, 'tier_required')
+        throw new D3ROError(ErrorCode.FeatureNotAvailable, 'Pro+ required for voice conversation')
+      }
+    } catch (err) {
+      if (err instanceof D3ROError) throw err
+    }
+
+    this._isActive = true
+    this._setState('listening')
+    this._startListening()
+    logger.info('Voice conversation session started')
+  }
+
+  /**
+   * 대화 세션 종료.
+   */
+  stopSession(): void {
+    if (!this._isActive) return
+
+    this._stopListening()
+    getTTSPlaybackService().stop()
+    getLocalLLMService().cancelGeneration()
+
+    this._isActive = false
+    this._setState('idle')
+    logger.info('Voice conversation session stopped')
+  }
+
+  /**
+   * 텍스트 메시지를 직접 전송 (키보드 입력).
+   */
+  async sendTextMessage(text: string): Promise<void> {
+    if (!this._isActive) {
+      throw new D3ROError(ErrorCode.ConversationNoActiveSession, 'No active conversation session')
+    }
+
+    await this._processUserMessage(text)
+  }
+
+  /**
+   * 현재 LLM 응답 또는 TTS 재생을 취소.
+   */
+  cancelResponse(): void {
+    getLocalLLMService().cancelGeneration()
+    getTTSPlaybackService().stop()
+    if (this._isActive) {
+      this._setState('listening')
+      this._startListening()
+    }
+  }
+
+  /**
+   * 대화 히스토리 초기화.
+   */
+  clearHistory(): void {
+    this._messages = []
+    this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.STATE_CHANGED, this.getSessionInfo())
+  }
+
+  // ── 내부 로직 ──
+
+  private _setState(state: ConversationState): void {
+    this._state = state
+    this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.STATE_CHANGED, this.getSessionInfo())
+    this.emit('state-changed', state)
+  }
+
+  private _startListening(): void {
+    this._audioBuffers = []
+    const audioService = getAudioCaptureService()
+
+    if (!this._audioListenerBound) {
+      audioService.on('audio-data', this._onAudioData)
+      this._audioListenerBound = true
+    }
+
+    audioService.start().catch((err) => {
+      logger.error('Failed to start audio capture for conversation:', err)
+      this._emitError('stt', 'Failed to start microphone')
+    })
+  }
+
+  private _stopListening(): void {
+    const audioService = getAudioCaptureService()
+    if (this._audioListenerBound) {
+      audioService.off('audio-data', this._onAudioData)
+      this._audioListenerBound = false
+    }
+    audioService.stop().catch(() => { /* ignore */ })
+    this._audioBuffers = []
+  }
+
+  private _onAudioData = (payload: { buffer: Buffer }): void => {
+    if (this._state !== 'listening') return
+    this._audioBuffers.push(payload.buffer)
+  }
+
+  /**
+   * 녹음 완료 (UI에서 stop 버튼 클릭 시 호출).
+   * 수집된 오디오를 STT로 전사 후 LLM 대화 진행.
+   */
+  async finishListening(): Promise<void> {
+    if (this._state !== 'listening' || this._audioBuffers.length === 0) return
+
+    this._stopListening()
+    this._setState('thinking')
+
+    const audioBuffer = Buffer.concat(this._audioBuffers)
+    this._audioBuffers = []
+
+    // 최소 오디오 길이 체크 (500ms @ 16kHz 16bit mono)
+    const minBytes = 16000 * 2 * 0.5
+    if (audioBuffer.length < minBytes) {
+      this._setState('listening')
+      this._startListening()
+      return
+    }
+
+    try {
+      // STT
+      const sttService = getLocalSTTService()
+      const language = (configGet('sttLanguage') as string | undefined) ?? 'auto'
+      const result = await sttService.transcribe(audioBuffer, { language, vadFilter: true })
+
+      if (!result.text || result.text.trim().length === 0) {
+        this._setState('listening')
+        this._startListening()
+        return
+      }
+
+      await this._processUserMessage(result.text.trim())
+    } catch (err) {
+      logger.error('STT failed in conversation:', err)
+      this._emitError('stt', err instanceof Error ? err.message : 'STT failed')
+      this._setState('listening')
+      this._startListening()
+    }
+  }
+
+  private async _processUserMessage(text: string): Promise<void> {
+    // 사용자 메시지 추가
+    const userMsg: ConversationMessage = {
+      id: nanoid(),
+      role: 'user',
+      content: text,
+      timestamp: Date.now(),
+    }
+    this._messages.push(userMsg)
+    this._trimHistory()
+
+    this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.USER_MESSAGE, userMsg)
+    this._setState('thinking')
+
+    try {
+      // Ollama /api/chat 호출 (스트리밍)
+      const llmService = getLocalLLMService()
+      const chatMessages = this._buildChatMessages()
+
+      const assistantMsgId = nanoid()
+      let accumulated = ''
+      const ttsSentences: string[] = []
+      let sentenceBuffer = ''
+
+      const generator = llmService.chatStream(chatMessages)
+
+      for await (const token of generator) {
+        accumulated += token
+
+        // 렌더러에 델타 전송
+        const delta: ConversationAssistantDelta = {
+          messageId: assistantMsgId,
+          delta: token,
+          accumulated,
+        }
+        this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.ASSISTANT_DELTA, delta)
+
+        // 문장 단위 TTS 큐잉
+        sentenceBuffer += token
+        const sentenceEnd = sentenceBuffer.match(/[.!?。！？]\s*/g)
+        if (sentenceEnd) {
+          const lastEnd = sentenceBuffer.lastIndexOf(sentenceEnd[sentenceEnd.length - 1])
+          const completeSentence = sentenceBuffer.slice(
+            0,
+            lastEnd + sentenceEnd[sentenceEnd.length - 1].length,
+          )
+          sentenceBuffer = sentenceBuffer.slice(
+            lastEnd + sentenceEnd[sentenceEnd.length - 1].length,
+          )
+          if (completeSentence.trim()) {
+            ttsSentences.push(completeSentence.trim())
+          }
+        }
+      }
+
+      // 남은 텍스트도 TTS 큐에 추가
+      if (sentenceBuffer.trim()) {
+        ttsSentences.push(sentenceBuffer.trim())
+      }
+
+      // 어시스턴트 메시지 저장
+      const assistantMsg: ConversationMessage = {
+        id: assistantMsgId,
+        role: 'assistant',
+        content: accumulated,
+        timestamp: Date.now(),
+      }
+      this._messages.push(assistantMsg)
+      this._trimHistory()
+
+      const completeEvent: ConversationAssistantMessage = {
+        messageId: assistantMsgId,
+        content: accumulated,
+      }
+      this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.ASSISTANT_MESSAGE, completeEvent)
+
+      // TTS 재생
+      if (ttsSentences.length > 0) {
+        this._setState('speaking')
+        this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.TTS_STARTED, {})
+
+        const ttsService = getTTSPlaybackService()
+        await ttsService.speakSentences(ttsSentences)
+
+        this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.TTS_FINISHED, {})
+      }
+
+      // 재생 완료 → 다시 listening
+      if (this._isActive) {
+        this._setState('listening')
+        this._startListening()
+      }
+    } catch (err) {
+      logger.error('LLM chat failed in conversation:', err)
+      this._emitError('llm', err instanceof Error ? err.message : 'LLM failed')
+      if (this._isActive) {
+        this._setState('listening')
+        this._startListening()
+      }
+    }
+  }
+
+  private _buildChatMessages(): Array<{ role: string; content: string }> {
+    const chatMsgs: Array<{ role: string; content: string }> = [
+      { role: 'system', content: SYSTEM_PROMPT },
+    ]
+
+    for (const msg of this._messages) {
+      if (msg.role === 'user' || msg.role === 'assistant') {
+        chatMsgs.push({ role: msg.role, content: msg.content })
+      }
+    }
+
+    return chatMsgs
+  }
+
+  private _trimHistory(): void {
+    // user+assistant 쌍 기준으로 최근 MAX_HISTORY_TURNS개만 유지
+    const pairs: ConversationMessage[] = []
+    let turnCount = 0
+
+    for (let i = this._messages.length - 1; i >= 0; i--) {
+      pairs.unshift(this._messages[i])
+      if (this._messages[i].role === 'user') {
+        turnCount++
+        if (turnCount >= MAX_HISTORY_TURNS) break
+      }
+    }
+
+    this._messages = pairs
+  }
+
+  private _emitError(phase: ConversationError['phase'], message: string): void {
+    const error: ConversationError = { message, phase }
+    this._sendToRenderer(IPC_CHANNELS.VOICE_CONVERSATION.ERROR, error)
+    this.emit('error', error)
+  }
+
+  private _sendToRenderer(channel: string, data: unknown): void {
+    try {
+      const mainWindow = getMainWindow()
+      if (mainWindow && !mainWindow.isDestroyed()) {
+        mainWindow.webContents.send(channel, data)
+      }
+    } catch {
+      // 윈도우 없으면 무시
+    }
+  }
+
+  dispose(): void {
+    this.stopSession()
+    this.removeAllListeners()
+  }
+}
+
+// ── 싱글톤 ──
+let instance: VoiceConversationService | null = null
+
+export function getVoiceConversationService(): VoiceConversationService {
+  if (!instance) {
+    instance = new VoiceConversationService()
+  }
+  return instance
+}