Support pnpm instead of npm in OpenClaw Android installer

[Frozen12]

Hello,
Thank you for the OpenClaw Android installer. It greatly simplifies running OpenClaw in Termux.
Currently, the installer uses npm for dependency installation. It would be helpful if pnpm support could be added as an alternative package manager.
Reasons:
Faster dependency installation
Reduced disk usage due to pnpm's content-addressable storage
Better performance in constrained environments like Android/Termux
A possible change would be allowing the installer to run:
pnpm install
instead of npm install, or providing an option to choose the package manager during installation.
Thank you for your work on the project.

[simonsbot]

Thanks for the suggestion! Using pnpm for faster installs and lower disk usage makes a lot of sense, especially in a constrained Termux environment on Android.

That said, adding pnpm support would require some consideration — pnpm itself needs to be installed (and maintained) in the Termux environment, and the install scripts would need to handle both package managers gracefully. It's a reasonable feature request, but worth noting that pnpm's symlink/hardlink approach can sometimes behave differently on Android's filesystem, so it would need some testing. If you're comfortable modifying the installer script locally, swapping npm install for pnpm install after installing pnpm via npm i -g pnpm should work in most cases — feel free to give it a try and open a PR if it works well for you!