[Enhancement] Save setup config to ~/.dev-setup.json

[chahe-dridi]

After a successful install, save the results to ~/.dev-setup.json:

{
  "version": "1.0.0",
  "installedAt": "2024-01-15T10:30:00Z",
  "os": "macOS",
  "tools": {
    "git": "2.43.0",
    "nodejs": "20.11.0"
  }
}

This enables future --update and --sync commands, 
and lets developers commit their setup to a dotfiles repo.