Notice the /src-electron/package.json file in your generated /src-electron folder. The purpose of it is for you to be able to install packages used by the Electron mode directly under this folder (and not pollute the common /src).

{
  "name": "quasar-electron-app",
  "version": "1.0.0",
  "description": "Quasar Electron Folder",
  "private": true,
  "type": "module",
  "devDependencies": {
    "@electron/packager": "^20.0.0",
    "electron": "^41.3.0"
  }
}

Installing Electron specific packages:

# run in /src-electron for runtime deps (will be embedded to /dist):
pnpm add <deps>

# run in /src-electron for deps used by the build system (eg. "electron")
pnpm add -D <dev-deps>