Agents from MD instead of YAML

[vorburger]

To follow-up on #1464,

it could be fun to make https://docs.enola.dev/tutorial/agents be able to read MD instead of only YAML (as it currently is).

So either the instruction or the prompt from #1645 would be in the "body" of the MD. The rest still in YAML in the MD "front matter".

So like https://github.com/google/dotprompt. Not necessarily fully compatible with it, but perhaps a superset. TBD TBC.

Or to run https://github.com/glaforge/gcli-mdrun MD - so it should just also work WITHOUT any YAML front matter header at all.