hark-system-hook: use correct mark for cage from kiln
%kick :_(this (drop safe-watch:kiln:cc))
::
%fact
- ?. ?=(%kiln-vats-diff p.cage.sign) `this
+ ?. ?=(%kiln-vats-diff-0 p.cage.sign) `this
=+ !<(=diff:hood q.cage.sign)
?+ -.diff `this
::
