Minimal default LiveView hosting the Etcher annotation layer for the reader pages (which are controller-rendered — this embedded LiveView supplies the channel Etcher's hook pushes events through).
Persists shape saves through the configured Manhwa.Annotations
adapter. It deliberately renders no comment UI — hosts that want
comment threads on shapes (composer modals, replies, likes) should
ship their own LiveView and point config :manhwa, :etcher_host
at it; the reader embeds whatever module is configured with the
session keys documented in Manhwa.Config.etcher_session/2.
Only compiled when the optional etcher dependency is present.