[FEATURE] add cli option --skills=name1,name2 to only install selected skill from github repo non-interactivelly

Feature Description Need cli options to install skill non interactively

Use Case CI/CD, or bootstrap scripts

Proposed Implementation add cli option --skills=name1,name2

Compatibility Consideration Please confirm:

• This feature maintains compatibility with Anthropic's SKILL.md specification
• This feature works across multiple AI agents (not just Claude Code)
• This feature aligns with the simplicity goal (.claude/skills only)