in Ignition 8.3 we ca use requestScan to scan the projects directory
is there a way to trigger from script/SDK a "Platform/Overview Scan File System"

to update gateway ressources ?
concern gateway or projects ?
Must be a question for @paul-griffith !
from the gatewayContext
we can reach ConfigurationManager and ProjectManager, so we can requestScan one or the other.
In some upcoming release (hopefully 8.3.7
) system.config will be added, which has a corresponding requestScan method as the project system.
If you're in an SDK context, though, go ahead with what you've got.