Vendor the using-vit skill copy into vit itself (Node built-ins, no npx, no network) and self-install it from the commands people and agents actually run, so it no longer depends on package-manager lifecycle hooks. - add src/lib/skill-install.js: best-effort ensureSkill() that copies the bundled skill into ~/.claude/skills/using-vit and ~/.agents/skills/using-vit, overwrite-refresh, per-target structured results, never throws - doctor/setup/login/postinstall all call ensureSkill() and report outcome - add `vit setup` as an exact alias of `vit doctor` - doctor detects the skill in either ~/.claude or ~/.agents; removes the stale "reinstall vit" guidance; --json stdout stays pure (install log to stderr) - doctor --json gains a skillInstall key (existing keys unchanged) - login ensures the skill on every invocation and prints a readiness line - postinstall drops npx/spawn for the vendored copy; stays best-effort, exits 0 - fix `vit --version` to read package.json (was hardcoded 0.1.0), works under node and bun Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>