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/tsconfig.json

@@ -3,6 +3,7 @@
   "references": [
     { "path": "./tsconfig.app.json" },
     { "path": "./tsconfig.node.json" },
-    { "path": "./tsconfig.vitest.json" }
+    { "path": "./tsconfig.vitest.json" },
+    { "path": "./tsconfig.electron.json" }
   ]
 }