toBool method
Converts string to boolean (case-insensitive).
Accepts: "true", "yes", "1".
Implementation
bool? toBool() {
if (this == null) return null;
final value = this!.toLowerCase().trim();
if (['true', 'yes', '1'].contains(value)) return true;
if (['false', 'no', '0'].contains(value)) return false;
return null;
}