support different front-end frameworks

[jaked]

not sure if this is easy to set up with Vite but it would be nice to be able to set a framework type on a cell somehow and render using that framework. Maybe Astro has some useful ideas / implementation here.

• maybe cells that aren't marked with a framework are executed server-side?
• maybe using JSX in a server-side cell renders static HTML?
• is there any point to trying to execute cells both server- and client-side like for SSR?