Chore: Tool for generating llms files

[m-brando]

Description

Create a tool to automatically generate and update llms.txt and llms-full.txt.

Currently, when we modify the docs, we have to manually copy and paste content into these files. This tool should automate the process and keep the following files in sync with the documentation:

https://docs.claudie.io/llms.txt
https://docs.claudie.io/llms-full.txt

The tool should extract content from the documentation Markdown files, strip out images, and output plain text only