feat(electron): add desktop application support with electron (#344)

* feat(electron): add desktop application support with electron

- implement complete Electron main process architecture with window management,
  app menu, IPC handlers, and settings window
- integrate Next.js server for production builds with embedded standalone server
- add configuration management with persistent storage and env file support
- create preload scripts with secure context bridge for renderer communication
- set up electron-builder configuration for multi-platform packaging (macOS,
  Windows, Linux)
- add GitHub Actions workflow for automated release builds
- include development scripts for hot-reload during Electron development

* feat(electron): enhance security and stability

- encrypt API keys using Electron safeStorage API before persisting to disk
- add error handling and rollback for preset switching failures
- extract inline styles to external CSS file and remove unsafe-inline from CSP
- implement dynamic port allocation with automatic fallback for production builds

* fix(electron): add maintainer field for Linux .deb package

- add maintainer email to linux configuration in electron-builder.yml
- required for building .deb packages

* fix(electron): use shx for cross-platform file copying

- replace Unix-only cp -r with npx shx cp -r
- add shx as devDependency for Windows compatibility

* fix(electron): fix runtime icon path for all platforms

- use icon.png directly instead of platform-specific formats
- electron-builder handles icon conversion during packaging
- macOS uses embedded icon from app bundle, no explicit path needed
- add icon.png to extraResources for Windows/Linux runtime access

* fix(electron): add security warning for plaintext API key storage

- warn user when safeStorage is unavailable (Linux without keyring)
- fail secure: throw error if encryption fails instead of storing plaintext
- prevent duplicate warnings with hasWarnedAboutPlaintext flag

* fix(electron): add remaining review fixes

- Add Windows ARM64 architecture support
- Add IPC input validation with config key whitelist
- Add server.js existence check before starting Next.js server
- Make afterPack throw error on missing directories
- Add workflow permissions for release job

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

.github/workflows/electron-release.yml

@@ -0,0 +1,100 @@
+name: Electron Release
+
+on:
+  push:
+    tags:
+      - "v*"
+  workflow_dispatch:
+    inputs:
+      version:
+        description: "Version tag (e.g., v0.4.5)"
+        required: false
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: macos-latest
+            platform: mac
+          - os: windows-latest
+            platform: win
+          - os: ubuntu-latest
+            platform: linux
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build Electron app
+        run: npm run dist:${{ matrix.platform }}
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Upload macOS artifacts
+        if: matrix.platform == 'mac'
+        uses: actions/upload-artifact@v4
+        with:
+          name: mac-build
+          path: |
+            release/*.dmg
+            release/*.zip
+          if-no-files-found: error
+
+      - name: Upload Windows artifacts
+        if: matrix.platform == 'win'
+        uses: actions/upload-artifact@v4
+        with:
+          name: win-build
+          path: |
+            release/*.exe
+          if-no-files-found: error
+
+      - name: Upload Linux artifacts
+        if: matrix.platform == 'linux'
+        uses: actions/upload-artifact@v4
+        with:
+          name: linux-build
+          path: |
+            release/*.AppImage
+            release/*.deb
+          if-no-files-found: error
+
+  release:
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    if: startsWith(github.ref, 'refs/tags/')
+
+    steps:
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: artifacts
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: |
+            artifacts/**/*.dmg
+            artifacts/**/*.zip
+            artifacts/**/*.exe
+            artifacts/**/*.AppImage
+            artifacts/**/*.deb
+          draft: true
+          generate_release_notes: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}