v0.20.2 — HTML scaffold client runtime

A focused patch closing the @refrakt-md/html scaffold's interactivity gap: the adapter ships the client runtime (@refrakt-md/html/client + @refrakt-md/behaviors) but template-html's build never bundles or references it, so a scaffolded static site has inert tabs, accordion, search, and theme-toggle. This milestone makes a scaffolded html site interactive out of the box.