prereg --check now refuses a loaded comparison whose ## No-gstack arm
section lacks masking:, install: or audit:, or says none for one of them
(PREREG_NO_GSTACK_ARM). On Capy, run agents inherit the instruction to load
the user-drive gstack skill, so the arm hides both Capy drives, checks that
no gstack is installed, and audits drive reads; an arm that read a gstack
skill file is contaminated and gets zero credit (TESTING_INTERNALS.md
#no-gstack-arm). The prereg template, /eval-plan, troubleshooting and the
two passing prereg fixtures carry the new lines. eval-plan's paragraph was
dieted to hold its context-budget ceiling.
Evidence: safety: keeps the no-gstack control uncontaminated (Captain order, FOUN-32 via GGST-6)
Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>