fix: use cross-env and shx for Windows-compatible npm scripts

[Akihiro2004]

The npm scripts in both packages used Unix-only shell syntax that breaks on Windows. Running pnpm dev or building/packing the plugin on Windows would fail immediately.

Changes:

• Added cross-env to claw-client devDependencies and updated the dev and start scripts to use it, so NEXT_OUTPUT=server gets set correctly on Windows instead of throwing a syntax error
• Added shx to claw-plugin devDependencies and updated the bundle-ui script to use shx rm -rf and shx cp -r instead of bare Unix commands that cmd.exe does not understand

Test Plan

1. Verified locally (pnpm ci passes)
2. Manually tested the plugin end-to-end with a running OpenClaw gateway
3. Ran pnpm dev on Windows and confirmed it starts without the NEXT_OUTPUT is not recognized error
4. Ran pnpm prepack on Windows and confirmed the static files copy over without rm or cp failing

[Aditya-thesys]

Hi @Akihiro2004 , thanks! for raising the fix.
Could you please remove package-lock.json file,since this repo is pnpm based.

[Akihiro2004]

Hi @Akihiro2004 , thanks! for raising the fix. Could you please remove package-lock.json file,since this repo is pnpm based.

Sure.

[Aditya-thesys]

nit: could you use latest cross env package version

[Aditya-thesys]

thanks! for the contribution

[zahlekhan]

Hey @Akihiro2004 thanks for the contribution.
We would love you on our Discord to share what you are using OpenClaw-OS for.
https://discord.com/invite/Pbv5PsqUSv