settings-store: add existence scry
=/ entry=(unit val) (~(get by bucket) key)
?~ entry [~ ~]
``settings-data+!>(entry+u.entry)
+ ::
+ [%x %has-bucket @ ~]
+ =* buc i.t.t.pax
+ =/ has-bucket=? (~(has by settings) buc)
+ ``noun+!>(has-bucket)
+ ::
+ [%x %has-entry @ @ ~]
+ =* buc i.t.t.pax
+ =* key i.t.t.t.pax
+ =/ =bucket (fall (~(get by settings) buc) ~)
+ =/ has-entry=? (~(has by bucket) key)
+ ``noun+!>(has-entry)
==
::
++ on-agent on-agent:def
