Add a documentation analysis step in core instructions

[pickleton89]

I have been working with agent-os and adopting it to my workflows (thinks for the product, it is great), and I was running into an issue that I would describe a product, say generating an MCP to a desktop application API, and it would plan without having the full documentation of the API, then I would have to fix all that after documentation was generated. I built into create-spec, and plan-product core instructions to ask user if there is local documentation or an url to got to look at documentation for use in these steps. Might be something to implement in your base system moving forward.