Replace the legacy vanilla HTML/CSS/JS pages with a SolidJS single-page
app (TanStack Router/Query, Ark UI, Tailwind v4) and embed its build
output into the Go binary via //go:embed. SPA routes fall back to
index.html. Includes the room chat/danmaku panel, color picker and
broadcaster overlay on the watch/publish pages. Add web/node_modules
and local data to .gitignore.
xuhongyuan