Add support for Gemini CLI and MCP

[redvelvets]

The current project only supports Claude Code and Cursor.
It should add support for Gemini CLI slash commands, including both toml-based and prompt-based definitions.

Gemini CLI’s slash commands can already be integrated with MCP prompts.
Using MCP to connect slash commands makes the integration simpler.

link:
https://cloud.google.com/blog/topics/developers-practitioners/gemini-cli-custom-slash-commands?utm_source=chatgpt.com