Selective skill install from a plugin

[tekumara]

I'd like to be able to select the skills in a plugin to install.

eg:

• dotagents add getsentry/skills would present a list of all skills from the plugin and allow me to interactively choose, like it does for multiple skills in a repo, eg: dotagents add openclaw/gogcli
• dotagents add getsentry/skills skill-writer would only install the skill-writer skill from the plugin