detectShell function
Implementation
String detectShell() {
final shell = Platform.environment['SHELL'] ?? '';
if (shell.contains('zsh')) return 'zsh';
if (shell.contains('bash')) return 'bash';
if (shell.contains('fish')) return 'fish';
if (shell.contains('nu')) return 'nushell';
if (shell.contains('pwsh') || shell.contains('powershell')) {
return 'powershell';
}
if (shell.isNotEmpty) return shell.split('/').last;
// Fallback
if (Platform.isWindows) return 'cmd';
return 'sh';
}