fix(web): make docs responsive with mobile drawer and site nav

[snhsish]

Makes the docs layout usable on mobile and adds site navigation.

• Sidebar hidden on mobile behind a hamburger-driven drawer (portaled to body so the sticky blurred header can't trap it)
• Docs header gains desktop site nav (Home, Download, Pricing, Docs, Blog, Support, GitHub); drawer lists docs nav first, site links below a divider
• Fixes content squeeze/overflow: min-w-0, break-words, responsive padding and MDX type scale, max-w-full on pre/tables