Expose SKILL.md

It's a known recommended practice these days to prefer CLI tools over MCPs since MCPs take lots of the context window.
But, I wasn't sure if my Claude Code will know how to use the new Alpaca CLI utility, which the MCP provides a list of tools.
In addition, I have noticed you do have some [SKILL.md](https://github.com/alpacahq/cli/blob/main/.agents/skills/alpaca-cli/SKILL.md) in your repo but I think it's not included in the brew package for Mac (`brew list alpacahq/tap/cli`) so I set to create something.

I gave my Claude a task - to create SKILL.md for itself, based on the linked skill file.

It created the attached SKILL.md. I thought it might be a good starter skill file to distribute with the CLI tool, passing it forward to you.

[SKILL.md](https://github.com/user-attachments/files/27019857/SKILL.md)