refactor(desktop): 替换 WebUI 为 Electron + electron-vite 桌面壳方案

- 使用 electron-vite 构建 main/preload，electron-builder 打包分发
- main process: dev 模式直连 localhost:3000，生产模式 spawn sidecar binary
- 添加 loading 页面，server 就绪前显示加载动画
- 更新 catalog 依赖: electron, electron-vite, electron-builder
- 移除 @webui-dev/bun-webui 依赖

apps/desktop/tsconfig.json

@@ -1,6 +1,7 @@
 {
-  "extends": "@furtherverse/tsconfig/bun.json",
+  "extends": "@furtherverse/tsconfig/base.json",
   "compilerOptions": {
-    "lib": ["ESNext", "DOM", "DOM.Iterable"]
-  }
+    "types": ["node"]
+  },
+  "include": ["src/main/**/*", "src/preload/**/*", "electron.vite.config.ts"]
 }