Add checkProfileSize / checkGroupProfileSize that encode the full
ChatMessage and check against maxEncodedInfoLength, so a long
displayName/bio combined with a near-max image is also caught at
command time instead of failing later at send time with CEException.
Run alongside the existing checkProfileImageSize (image-only cap of
12500 bytes, matching mobile UIs) in CreateActiveUser, updateProfile_,
newGroup, runUpdateGroupProfile. Update genProfileImg to fit the cap.