feat(V2-5): macOS 빌드 지원 — 플랫폼 분기 + electron-builder mac 타겟 + CI

플랫폼 분기 (paths.ts):
- EXE_SUFFIX 상수로 sox/sidecar/ffmpeg 실행파일 확장자 통합
- Windows에선 .exe 자동 부착, Mac/Linux에선 빈 문자열
- 미사용 getProjectRoot 헬퍼 제거

런타임 서비스 Mac 분기:
- SoundEffectService: darwin → /usr/bin/afplay,
  linux → aplay 분기 추가 (execFile로 안전하게)
- ScreenContextService._getActiveWindowInfo:
  win32 → PowerShell + user32.dll (기존),
  darwin → osascript (System Events frontmost process + 윈도우 타이틀)
  Linux는 미지원 (null)

electron-builder.yml:
- mac 타겟 추가 (dmg + zip, arm64 + x64 매트릭스)
- hardenedRuntime, gatekeeperAssess, entitlements 설정
- extendInfo로 NSMicrophoneUsage / NSCameraUsage / NSAppleEvents /
  NSSystemAdministration 권한 메시지
- dmg 레이아웃 (드래그 to /Applications)
- linux AppImage placeholder
- notarize: false 기본, NOTARIZE 환경변수로 활성화

build/entitlements.mac.plist:
- allow-jit, allow-unsigned-executable-memory (Electron 필수)
- audio-input, camera, network.client
- automation.apple-events (활성 윈도우 조회용)
- files.user-selected.read-write
- allow-dyld-environment-variables (sox/ffmpeg 라이브러리 로드)

scripts/build-sidecar.py:
- IS_WINDOWS / IS_MACOS / EXE_SUFFIX 도입
- Windows에서만 --noconsole 플래그
- 빌드 결과 경로 + size 출력 플랫폼 통합

scripts/install-sox.sh (신규):
- Mac/Linux용 SoX 번들 스크립트
- macOS는 otool로 dylib 의존성 식별 후 함께 복사,
  install_name_tool로 rpath를 @loader_path로 변경
- electron-builder의 extraResources 대상 디렉토리에 배치

resources/icons/ (신규):
- README.md만 커밋, 실제 아이콘 파일은 분리
- sips/iconutil/imagemagick으로 .icns/.ico/.png 생성 가이드

.github/workflows/build-mac.yml (신규):
- macos-14 runner (Apple Silicon), arm64/x64 matrix
- brew sox, npm install, @electron/rebuild,
  install-sox.sh, build-sidecar.py, electron-builder dist
- CSC/NOTARIZE 환경변수 자동 처리
- artifact 업로드 (dmg + zip, retention 7일)

docs/v2/phase-V2-5-mac-guide.md (신규):
- 사전 조건, 시스템 의존성, dev 실행, dist 빌드,
  Code signing + Notarization, CI 트리거, 트러블슈팅

검증 (Windows에서):
- typecheck 통과 (Mac 분기 추가에도 회귀 없음)
- build 통과
- dev 런타임 정상

Mac 검증은 사용자 본인 Mac에서 수행 (V2-5 사용자 액션).

.github/workflows/build-mac.yml

@@ -0,0 +1,95 @@
+name: Build macOS
+
+on:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch:
+    inputs:
+      notarize:
+        description: 'Apple Notarization 활성화'
+        required: false
+        default: 'false'
+        type: choice
+        options:
+          - 'false'
+          - 'true'
+
+jobs:
+  build:
+    name: Build & Package (macOS)
+    runs-on: macos-14   # arm64 (Apple Silicon)
+    timeout-minutes: 60
+
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: [arm64, x64]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: 'npm'
+
+      - name: Setup Python (sidecar 빌드용)
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install system deps (sox)
+        run: brew install sox
+
+      - name: Install npm dependencies
+        run: npm install
+
+      - name: Bundle SoX into resources
+        working-directory: apps/desktop
+        run: bash scripts/install-sox.sh
+
+      - name: Install Python dependencies
+        working-directory: apps/desktop
+        run: |
+          pip install pyinstaller
+          pip install -r sidecar/requirements.txt
+
+      - name: Build sidecar (PyInstaller)
+        working-directory: apps/desktop
+        run: python scripts/build-sidecar.py
+
+      - name: Rebuild native modules for Electron
+        run: npx --yes @electron/rebuild@3 --version=33.4.11
+
+      - name: Build renderer/preload/main
+        run: npm run build
+
+      - name: electron-builder dist (mac, ${{ matrix.arch }})
+        working-directory: apps/desktop
+        env:
+          # Apple 서명/공증 (notarize=true일 때만 사용)
+          APPLE_ID: ${{ secrets.APPLE_ID }}
+          APPLE_APP_SPECIFIC_PASSWORD: ${{ secrets.APPLE_APP_SPECIFIC_PASSWORD }}
+          APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
+          CSC_LINK: ${{ secrets.MAC_CERT_P12_BASE64 }}
+          CSC_KEY_PASSWORD: ${{ secrets.MAC_CERT_P12_PASSWORD }}
+          NOTARIZE: ${{ inputs.notarize || 'false' }}
+        run: |
+          if [ "$NOTARIZE" = "true" ] && [ -n "$APPLE_ID" ]; then
+            npx electron-builder --mac --${{ matrix.arch }} -c.mac.notarize=true
+          else
+            npx electron-builder --mac --${{ matrix.arch }} -c.mac.notarize=false
+          fi
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: d3ro-voice-mac-${{ matrix.arch }}
+          path: |
+            apps/desktop/release/*.dmg
+            apps/desktop/release/*.zip
+          if-no-files-found: error
+          retention-days: 7