- Replace $INSTALL_NPM (npm.cmd) with $NPM_CLI (npm-cli.js) + $INSTALL_NODE
- Use --prefix instead of Push-Location to avoid CWD issues in irm|iex pipe
- Restore PATH for downloaded Node (npm-cli.js internally needs node in PATH)
- Use [IO.File]::WriteAllText with BOM-free UTF8 for package.json/config/skills
- Add debug output before npm install for easier troubleshooting