Upgrade the MeshCore bot to talk the DongLoRa Protocol v2 via donglora 1.0.0.
* BotRuntime now holds a donglora.Dongle instead of a raw serial conn. All transmit / receive / ADVERT plumbing goes through the async Dongle surface.
* Drop the direct pyserial imports; SerialException handling is now dongle-level (reconnect is handled by donglora.connect()).
* Update constants and dispatch to match the Dongle accessors (info, set_config, transmit, start_rx) exposed by the 1.0 client.