Add guide for how to create a dashboard using OpenUI on docs

[rabisg]

[Adarshhic]

Hi! @rabisg I'd like to work on this issue if it's still available.
My plan would be a step-by-step guide covering:

1.Scaffolding an app with @openuidev/cli
2.Defining/using a dashboard-oriented component library (charts, tables, stat cards)
3.Generating the system prompt from that library
4.Streaming and rendering the output with
5.A worked example — e.g. a simple metrics dashboard with a chart + table + summary cards

Since the issue doesn't have a description, could you confirm this scope is right, or point me toward what you had in mind? Also happy to adjust based on where you'd like this to live in the docs/ site.
This would be my first contribution to OpenUI — let me know if I can go ahead!