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/src/main/index.ts

@@ -0,0 +1,122 @@
+import { spawn } from 'node:child_process'
+import { join } from 'node:path'
+import { app, BrowserWindow, shell } from 'electron'
+
+const DEV_SERVER_URL = 'http://localhost:3000'
+const PROD_SERVER_PORT = 23_410
+
+let mainWindow: BrowserWindow | null = null
+let serverProcess: ReturnType<typeof spawn> | null = null
+
+const isServerReady = async (url: string): Promise<boolean> => {
+  try {
+    const response = await fetch(url, { method: 'HEAD' })
+    return response.ok
+  } catch {
+    return false
+  }
+}
+
+const waitForServer = async (
+  url: string,
+  timeoutMs = 15_000,
+): Promise<boolean> => {
+  const start = Date.now()
+  while (Date.now() - start < timeoutMs) {
+    if (await isServerReady(url)) return true
+    await new Promise<void>((resolve) => setTimeout(resolve, 200))
+  }
+  return false
+}
+
+const spawnServer = (): string => {
+  const binaryName = process.platform === 'win32' ? 'server.exe' : 'server'
+  const binaryPath = join(process.resourcesPath, binaryName)
+
+  serverProcess = spawn(binaryPath, [], {
+    env: {
+      ...process.env,
+      PORT: String(PROD_SERVER_PORT),
+      HOST: '127.0.0.1',
+    },
+    stdio: 'pipe',
+  })
+
+  serverProcess.stdout?.on('data', (data: Buffer) => {
+    console.log(`[server] ${data.toString().trim()}`)
+  })
+
+  serverProcess.stderr?.on('data', (data: Buffer) => {
+    console.error(`[server] ${data.toString().trim()}`)
+  })
+
+  serverProcess.on('error', (err) => {
+    console.error('Failed to start server:', err)
+  })
+
+  return `http://127.0.0.1:${PROD_SERVER_PORT}`
+}
+
+const getServerUrl = (): string => {
+  if (!app.isPackaged) {
+    return DEV_SERVER_URL
+  }
+  return spawnServer()
+}
+
+const createWindow = async () => {
+  mainWindow = new BrowserWindow({
+    width: 1200,
+    height: 800,
+    show: false,
+    webPreferences: {
+      preload: join(__dirname, '../preload/index.mjs'),
+      sandbox: true,
+    },
+  })
+
+  mainWindow.webContents.setWindowOpenHandler(({ url }) => {
+    shell.openExternal(url)
+    return { action: 'deny' }
+  })
+
+  mainWindow.show()
+
+  const serverUrl = getServerUrl()
+
+  console.log(`Waiting for server at ${serverUrl}...`)
+  const ready = await waitForServer(serverUrl)
+  if (!ready) {
+    console.error(
+      app.isPackaged
+        ? 'Server binary did not start in time.'
+        : 'Dev server not responding. Run `bun dev` in apps/server first.',
+    )
+    app.quit()
+    return
+  }
+
+  console.log(`Loading ${serverUrl}`)
+  mainWindow.loadURL(serverUrl)
+}
+
+app.whenReady().then(createWindow)
+
+app.on('window-all-closed', () => {
+  if (process.platform !== 'darwin') {
+    app.quit()
+  }
+})
+
+app.on('activate', () => {
+  if (BrowserWindow.getAllWindows().length === 0) {
+    createWindow()
+  }
+})
+
+app.on('before-quit', () => {
+  if (serverProcess) {
+    serverProcess.kill()
+    serverProcess = null
+  }
+})