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/notify.py

@@ -0,0 +1,57 @@
+"""Notify platform for Reticulum.
+
+Exposes a ``notify`` entity that sends an LXMF message to the configured
+default recipient. For arbitrary destinations use the ``reticulum.send_message``
+service instead.
+"""
+
+from __future__ import annotations
+
+from homeassistant.components.notify import NotifyEntity, NotifyEntityFeature
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.exceptions import ServiceValidationError
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from .const import CONF_DEFAULT_RECIPIENT, CONF_DELIVERY_METHOD, DEFAULT_DELIVERY_METHOD, DOMAIN
+from .entity import ReticulumEntity
+from .reticulum_client import ReticulumError, ReticulumManager
+
+
+async def async_setup_entry(
+    hass: HomeAssistant,
+    entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
+    """Set up the Reticulum notify entity."""
+    manager: ReticulumManager = hass.data[DOMAIN][entry.entry_id].manager
+    async_add_entities([ReticulumNotify(manager, entry)])
+
+
+class ReticulumNotify(ReticulumEntity, NotifyEntity):
+    """Send LXMF messages to the default recipient."""
+
+    _attr_translation_key = "message"
+    _attr_icon = "mdi:message-fast"
+    _attr_supported_features = NotifyEntityFeature.TITLE
+
+    def __init__(self, manager: ReticulumManager, entry: ConfigEntry) -> None:
+        super().__init__(manager, entry.entry_id)
+        self._entry = entry
+        self._attr_unique_id = f"{entry.entry_id}_notify"
+
+    async def async_send_message(self, message: str, title: str | None = None) -> None:
+        recipient = self._entry.options.get(CONF_DEFAULT_RECIPIENT)
+        if not recipient:
+            raise ServiceValidationError(
+                "No default recipient configured. Set one in the Reticulum "
+                "integration options, or use the reticulum.send_message service "
+                "with an explicit destination."
+            )
+        method = self._entry.options.get(CONF_DELIVERY_METHOD, DEFAULT_DELIVERY_METHOD)
+        try:
+            await self._manager.async_send_message(
+                recipient, message, title=title or "", method=method
+            )
+        except ReticulumError as err:
+            raise ServiceValidationError(str(err)) from err