Default for projects should be claude not gemini

```
% skilz install vercel-labs/agent-skills/vercel-react-best-practices -p
Installed: vercel-labs/agent-skills/vercel-react-best-practices -> Gemini CLI (project)

# Workaround
% skilz install vercel-labs/agent-skills/vercel-react-best-practices -p --agent claude 
Installed: vercel-labs/agent-skills/vercel-react-best-practices -> Claude Code (project)
```