Update site to be more LLM/AI agent friendly

[notmandatory]

See cloudflare tool suggested by @GBKS on discord.

"Following up on your question, Cloudflare released a useful tool to get websites agent-ready. I just implemented a lot of the basic content changes in the Bitcoin Design Guide this morning, and it was pretty straightforward.
https://isitagentready.com/
BitcoinDesign/Guide#1228"

[reez]

Thanks @GBKS !

[notmandatory]

Maybe we can find or LLM create a version of the vitepress-plugin-llms for zensical ?

EDIT: looks like already a backlog issue for the zensical team: zensical/backlog#92

[reez]

[notmandatory]

partially fixed by #281