refactor: migrate PDF export to desktop runtime abstraction

- Extract desktop-specific logic into src/services/desktop.ts
- Add runtime detection for Electron vs Tauri environments
- Simplify NoteEditor by delegating PDF export to desktop service
- Update printExport.ts to remove unused storage helpers
- Add Electron main process files in electron/ directory
- Update vite config and types for Electron integration
- Update .gitignore and package.json for Electron workflow

package.json

@@ -3,9 +3,14 @@
   "private": true,
   "version": "0.2.2",
   "type": "module",
+  "main": "electron/main.cjs",
   "scripts": {
     "dev": "vite",
+    "dev:renderer": "vite",
+    "dev:electron": "wait-on tcp:1420 && cross-env ELECTRON_RENDERER_URL=http://localhost:1420 electron .",
+    "dev:desktop": "concurrently -k \"npm:dev:renderer\" \"npm:dev:electron\"",
     "build": "tsc && vite build",
+    "desktop": "electron .",
     "preview": "vite preview",
     "tauri": "tauri"
   },
@@ -34,9 +39,13 @@
     "@types/turndown": "^5.0.6",
     "@vitejs/plugin-react": "^4.6.0",
     "autoprefixer": "^10.4.27",
+    "concurrently": "^9.2.1",
+    "cross-env": "^10.1.0",
+    "electron": "^37.3.1",
     "postcss": "^8.5.8",
     "tailwindcss": "^3.4.19",
     "typescript": "~5.8.3",
-    "vite": "^7.0.4"
+    "vite": "^7.0.4",
+    "wait-on": "^8.0.5"
   }
 }