MERLIN RESET

This wipes only the MERLIN app's own keys on this exact origin. It does not touch any other site data, cookies, or localStorage keys.

Will remove:
neural_face_v13 (face signature)
neural_pin_salt_v1 (PIN salt)
neural_pin_check_v1 (PIN verification hash)
neural_fail_count_v1 (failed attempt counter)
neural_lock_until_v1 (lockout timestamp)