Add Fresh Harvest integration scaffold

Implements the freshharvest.com two-step login handshake, config flow,
6-hour polling coordinator, and four delivery sensors. Portal page parsing
is not implemented; async_get_next_delivery raises until the account HTML
is mapped against a signed-in session.

custom_components/freshharvest/coordinator.py

@@ -0,0 +1,39 @@
+"""Polling coordinator for Fresh Harvest."""
+
+from __future__ import annotations
+
+import logging
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.exceptions import ConfigEntryAuthFailed
+from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
+
+from .api import Delivery, FreshHarvestAuthError, FreshHarvestClient, FreshHarvestError
+from .const import DOMAIN, UPDATE_INTERVAL
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class FreshHarvestCoordinator(DataUpdateCoordinator[Delivery]):
+    """Fetch the account's next delivery."""
+
+    def __init__(
+        self, hass: HomeAssistant, entry: ConfigEntry, client: FreshHarvestClient
+    ) -> None:
+        super().__init__(
+            hass,
+            _LOGGER,
+            name=DOMAIN,
+            update_interval=UPDATE_INTERVAL,
+            config_entry=entry,
+        )
+        self.client = client
+
+    async def _async_update_data(self) -> Delivery:
+        try:
+            return await self.client.async_get_next_delivery()
+        except FreshHarvestAuthError as err:
+            raise ConfigEntryAuthFailed(str(err)) from err
+        except FreshHarvestError as err:
+            raise UpdateFailed(str(err)) from err