Move the Svelte dashboard out of internal/web into its own top-level
frontend/ so it can be built and hosted independently, and make the
subidx binary API-only: drop the embedded dist and the catch-all /
handler, so unknown paths return a plain 404.
The frontend already knew how to live apart (VITE_API_BASE, -cors-origins,
vercel.json), so only the embed glue is gone. Also wire in Vercel Web
Analytics via @vercel/analytics.