docket: add scry endpoint for app versions
Applications might want to do rudimentary version control prior to
scrying and other such operations.
%+ turn ~(tap by charges)
|= [=desk =charge]
[desk (get-light-charge charge)]
+ ::
+ [%x %charges @ %version ~]
+ ?~ charge=(~(get by charges) i.t.t.path)
+ [~ ~]
+ ``noun+!>(version.docket.u.charge)
==
::
++ on-agent
