Auth: move to use the new Router

Nextjs: fix image optimization routing

Router: fix missing x-forwarded-host header

SSR Sites: allow customizing server timeout

closes sst#5207

Examples: sync playground

Astro: fix type error

closes sst#5588

StaticSite: set default error page to index.html

Router: allow override origin connection config

Nextjs: fix CloudFront error for image optimization routes

Docs: pin sst version