fix(desktop): point main to preload/index.mjs (electron-vite outputs .mjs not .js)

Onboarding step 2 was showing 'Renderer is not connected to the main process'
because BrowserWindow.webPreferences.preload pointed at .js while
electron-vite outputs .mjs. Electron 33+ supports .mjs preload natively.

Signed-off-by: hqhq1025 <1506751656@qq.com>

Author: hqhq1025

apps/desktop/src/main/index.ts

@@ -23,7 +23,7 @@ function createWindow(): void {
     backgroundColor: BRAND.backgroundColor,
     show: false,
     webPreferences: {
-      preload: join(__dirname, '../preload/index.js'),
+      preload: join(__dirname, '../preload/index.mjs'),
       sandbox: true,
       contextIsolation: true,
       nodeIntegration: false,