Add Reticulum/LXMF integration for Home Assistant

Custom integration connecting Home Assistant to a Reticulum network over a
TCPClientInterface and exchanging LXMF messages, with an Assist conversation
bridge, notify entity, sensors (incl. interface telemetry), buttons, services,
bus events and device triggers.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

custom_components/reticulum/binary_sensor.py

@@ -0,0 +1,40 @@
+"""Binary sensor platform for Reticulum."""
+
+from __future__ import annotations
+
+from homeassistant.components.binary_sensor import (
+    BinarySensorDeviceClass,
+    BinarySensorEntity,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from .const import DOMAIN
+from .entity import ReticulumEntity
+from .reticulum_client import ReticulumManager
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up the Reticulum connectivity binary sensor."""
+    manager: ReticulumManager = hass.data[DOMAIN][entry.entry_id].manager
+    async_add_entities([ReticulumConnectivity(manager, entry.entry_id)])
+
+
+class ReticulumConnectivity(ReticulumEntity, BinarySensorEntity):
+    """Reports whether the outbound Reticulum interface is online."""
+
+    _attr_translation_key = "connected"
+    _attr_device_class = BinarySensorDeviceClass.CONNECTIVITY
+
+    def __init__(self, manager: ReticulumManager, entry_id: str) -> None:
+        super().__init__(manager, entry_id)
+        self._attr_unique_id = f"{entry_id}_connected"
+
+    @property
+    def is_on(self) -> bool:
+        return self._manager.state.interface_online