Biometric Authentication

Rule 1: Check availability before showing biometric UI

// ✅ Check what's available before prompting
fun BiometricManager.canAuthenticateWithBiometrics(): Boolean {
    val authenticators = BIOMETRIC_STRONG or DEVICE_CREDENTIAL
    return canAuthenticate(authenticators) == BiometricManager.BIOMETRIC_SUCCESS
}

// ✅ Detailed availability check
sealed interface BiometricAvailability {
    data object Available : BiometricAvailability
    data object NoHardware : BiometricAvailability
    data object NotEnrolled : BiometricAvailability
    data object Unavailable : BiometricAvailability
}