CompanionBackend speaks the companion frame protocol (stock MeshCore 1.17/1.18,
wadamesh extras handled) over a CompanionTransport: USB serial and TCP natively
(--serial / --tcp), Web Serial, Web Bluetooth and WebSocket in the browser (JS
glue in web/mesh/js, framing in C++). The stand-in gains the node-only events
(self info, raw RX, login, CLI, regions, contact removal) and computes the RX
log, advert routes, repeats heard and message route info from the node's raw
RX pushes, as the device does. Demo stays the default.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
