Revert to sandbox: false for preload compatibility

sandbox: true breaks @electron-toolkit/preload which needs
full Node.js require() unavailable in sandboxed preloads.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: parthmodi152

app/src/main/index.ts

@@ -30,7 +30,7 @@ function createWindow(): void {
     autoHideMenuBar: true,
     webPreferences: {
       preload: join(__dirname, '../preload/index.js'),
-      sandbox: true,
+      sandbox: false,
     },
   })