Makefile: CI=true npx --yes for skills add/remove
The trailing -y on `npx skills` goes to the skills CLI, not to npx
itself. On a fresh machine without cached skills@X.Y.Z, npx halts with
an interactive "Ok to proceed?" — blocking the install pipeline and any
coding-agent-driven install. --yes suppresses that prompt; CI=true is
belt-and-suspenders against any other TTY-gated checks in the npm
lifecycle.
Applied to both install-service (fresh-machine path) and uninstall-
service for consistency.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>