One Vite build emits dist/index.html and dist/preview.html sharing every
chunk; the only difference is one prepended bootstrap entry whose module
connects the worker host, so the page from the stock entry onward is the
served startup chain verbatim. The dist moves to a relative base so the
preview mounts under any static directory, and the served form anchors
deep SPA-fallback paths with a rendered <base href="/">. The preview-boot
e2e serves the real built pages, packs the VFS image when absent, and
holds the boot line's lowering contract, the interactive hero, and a
clean page-error channel in headless Chromium.
