Introduce LegacyDeviceSetupErrorEvent and two mappers for the
generate-activation-key and create-device endpoints. 403 on
activation-key maps to invalidIdentificator; 404 to deviceNotFound;
401 (already activated or B2B) unifies as deviceNotAvailable. On
create-device, 403 → invalidField and 404 → invalidActivationKey.
The view state now splits validation vs API errors with a
displayErrorKey extension, replacing the previous e.toString() leak
that could surface stack traces to users.
JulianAlcala
bf1032245a