feat(electron): scaffold electron-vite project structure

Initialize Wave 1 Electron integration with:
- electron v40.6.1, electron-vite v5.0.0, electron-builder v26.8.1
- Main entry point: electron/main/index.ts with app:// protocol registration
- Preload placeholder: electron/preload/index.ts for Wave 2 IPC
- electron.vite.config.ts with unified renderer chunk splitting strategy
- tsconfig.electron.json with ESNext module support
- Updated package.json with electron dependencies and scripts:
  - electron:dev, electron:build, electron:preview
- All original scripts (dev, build, test, etc) remain unchanged
- TypeScript compilation verified: tsc --noEmit passes
- Ready for Wave 2: IPC bridge and contextBridge exposure

dashboard/package.json

@@ -3,6 +3,7 @@
   "private": true,
   "version": "1.0.0",
   "type": "module",
+  "main": "./out/main/index.js",
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
@@ -10,7 +11,10 @@
     "preview": "vite preview",
     "format": "prettier --write \"src/**/*.{ts,tsx,css}\"",
     "test": "vitest",
-    "test:ui": "vitest --ui"
+    "test:ui": "vitest --ui",
+    "electron:dev": "electron-vite dev",
+    "electron:build": "electron-vite build",
+    "electron:preview": "electron-vite preview"
   },
   "dependencies": {
     "@codemirror/lang-css": "^6.3.1",
@@ -88,6 +92,9 @@
     "@vitejs/plugin-react": "^5.1.2",
     "@vitest/ui": "^4.0.18",
     "autoprefixer": "^10.4.22",
+    "electron": "^40.6.1",
+    "electron-builder": "^26.8.1",
+    "electron-vite": "^5.0.0",
     "eslint": "^9.39.1",
     "eslint-plugin-react-hooks": "^7.0.1",
     "eslint-plugin-react-refresh": "^0.4.24",