Add GitHub Actions workflow for automated builds and releases

Implements CI/CD pipeline that builds Electron app for Windows, macOS, and Linux platforms and automatically publishes releases when tags are pushed.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ishikawa-pro

.github/workflows/build-and-release.yml

@@ -0,0 +1,95 @@
+name: Build and Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: 'npm'
+          
+      - name: Install dependencies
+        run: npm ci
+        
+      - name: Install native dependencies (Linux)
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libnss3-dev libatk-bridge2.0-dev libdrm2 libxcomposite1 libxdamage1 libxrandr2 libgbm1 libxss1 libasound2-dev
+          
+      - name: Build application
+        run: npm run dist
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          
+      - name: Upload artifacts (macOS)
+        if: matrix.os == 'macos-latest'
+        uses: actions/upload-artifact@v4
+        with:
+          name: macos-build
+          path: |
+            dist/*.dmg
+            dist/*.zip
+            
+      - name: Upload artifacts (Windows)
+        if: matrix.os == 'windows-latest'
+        uses: actions/upload-artifact@v4
+        with:
+          name: windows-build
+          path: |
+            dist/*.exe
+            dist/*.msi
+            
+      - name: Upload artifacts (Linux)
+        if: matrix.os == 'ubuntu-latest'
+        uses: actions/upload-artifact@v4
+        with:
+          name: linux-build
+          path: |
+            dist/*.AppImage
+            dist/*.deb
+            dist/*.rpm
+
+  release:
+    if: startsWith(github.ref, 'refs/tags/')
+    needs: build
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: ./artifacts
+          
+      - name: Display structure of downloaded files
+        run: ls -la artifacts/
+        
+      - name: Create Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            artifacts/**/*
+          draft: false
+          prerelease: false
+          generate_release_notes: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}