Add Baby Tracker client and Home Assistant integration

Python client for the Baby Tracker sync server, reverse engineered from
the Android app (4.53), and a HACS-installable Home Assistant integration
built on it. Each baby gets a log calendar and summary sensors, and actions
add entries that sync back to the group.

Reading has been run against the real server. Uploading and running inside
real Home Assistant have not.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

custom_components/babytracker/__init__.py

@@ -0,0 +1,44 @@
+"""The Baby Tracker integration."""
+
+from __future__ import annotations
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import CONF_EMAIL, CONF_PASSWORD, Platform
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers import config_validation as cv
+from homeassistant.helpers.typing import ConfigType
+
+from .babytracker_api import BabyTrackerClient
+from .const import CONF_DEVICE_UUID, DEVICE_NAME, DOMAIN
+from .coordinator import BabyTrackerCoordinator
+from .services import async_setup_services
+
+PLATFORMS = [Platform.CALENDAR, Platform.SENSOR]
+
+CONFIG_SCHEMA = cv.config_entry_only_config_schema(DOMAIN)
+
+
+async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
+    async_setup_services(hass)
+    return True
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    client = BabyTrackerClient(
+        entry.data[CONF_EMAIL],
+        entry.data[CONF_PASSWORD],
+        device_uuid=entry.data[CONF_DEVICE_UUID],
+        device_name=DEVICE_NAME,
+        device_os_info=DEVICE_NAME,
+    )
+    # A later login to a different account is then refused rather than mixed in.
+    client.account_id = int(entry.unique_id)
+    coordinator = BabyTrackerCoordinator(hass, entry, client)
+    await coordinator.async_config_entry_first_refresh()
+    entry.runtime_data = coordinator
+    await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
+    return True
+
+
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    return await hass.config_entries.async_unload_platforms(entry, PLATFORMS)