Biometrics

BIOMETRIC AUTHENTICATION (Face ID / Touch ID):

• import LocalAuthentication; LAContext().evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics)
• Requires NSFaceIDUsageDescription permission (add CONFIG_CHANGES)
• Check canEvaluatePolicy first; fall back to passcode if biometrics unavailable
• LAContext().biometryType to detect .faceID vs .touchID vs .none
• Always provide manual unlock alternative (PIN/password)