maskSensitiveValue function
Function to mask sensitive value while preserving some structure
Implementation
String maskSensitiveValue(String value) {
if (value.isEmpty) return '';
if (value.length <= 4) return '*' * value.length;
// Preserve first and last character, mask the rest
return '${value[0]}${'*' * (value.length - 2)}${value[value.length - 1]}';
}