The skills CLI metadata.internal flag was never implemented (PRs #587
and #652 were both closed). All 6 skills were showing in the installer.
Move the 5 specialized skills (dogfood, electron, slack, vercel-sandbox,
agentcore) from skills/ to skill-data/, which the skills CLI does not
search. The bootstrap skill stays in skills/ for discovery. The Rust CLI
searches both directories so agent-browser skills list/get still serves
all 6.
