Effort-medium-nudge remote config now validated for effort-level ordering, plus fromEffort/toEffort treated as invalid fields

The parser for the server-served effort-medium-nudge copy now runs parsed config through a new validation wrapper Aet, which calls w3t to check that every level in fromEffort is strictly below toEffort using an ordering array om. If the ordering check fails, the config is rejected and g("effort_medium_nudge", "served_copy_invalid") is recorded. Also, when the initial safeParse fails and the invalid fields include fromEffort or toEffort, the app now discards the whole served copy instead of stripping just the bad fields and salvaging the rest, as it previously did.