Introduce thermal zones as config subentries

Each temperature sensor used to be its own "room", so a room with two
sensors counted twice and comfort importance was tied to sensors.

zones.py adds Zone: a name, one or more sensors with sensor weights, a
comfort weight, an optional target offset and adjacent zones (made
symmetric). Sensor weights only combine readings; comfort weights only
steer the MPC; neither touches the learned thermal coefficients.

Zones are config subentries (HA's native "Add zone" / edit / delete on
the integration page), with validation that a sensor belongs to one
zone and is not an outdoor source, and a sensor-weight step for
multi-sensor zones. Initial setup still asks for room sensors and
weights and creates one zone per sensor. Configure no longer asks for
rooms or weights.

Config entry version 3. Migrating from 2 turns each room sensor into a
one-sensor zone with its comfort weight and the sensor's entity ID as
the zone key, so learned models, forecast entities (now linked to their
zone, so deleting a zone removes them) and accuracy statistics carry
over. Older versions cannot load a version 3 entry; rolling back needs
the HA backup.

A zone learns only across polls that used the same sensors (a sensor
dropping out shifts the mean by its offset); the new poll outcome
"sensors_changed" reports this. Status renames: input_quality.zones
(per-sensor detail nested), excluded_zones, retired_zone_models; adds
zone_names. Invalid stored comfort weights now fall back to 1.0, so the
invalid_weights status is gone.

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

custom_components/heating_mpc/__init__.py

@@ -1,16 +1,19 @@
 """Heating MPC custom integration, initial release shadow-only."""
 from __future__ import annotations
 
+from types import MappingProxyType
+
 from homeassistant.const import Platform
-from homeassistant.config_entries import ConfigEntry
+from homeassistant.config_entries import ConfigEntry, ConfigSubentry
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.storage import Store
 from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.event import async_track_state_change_event
 
-from .const import CONF_HEATER, DOMAIN, CONF_OUTSIDE, WEATHER_SOURCES
+from .const import CONF_HEATER, CONF_ROOMS, CONF_WEIGHTS, DOMAIN, CONF_OUTSIDE, WEATHER_SOURCES
 from .weather_sources import sources_for
 from .coordinator import HeatingMPCCoordinator
+from .zones import SUBENTRY_ZONE, ZONE_KEY, ZONE_NAME, legacy_zone_data
 
 PLATFORMS: list[Platform] = [Platform.SENSOR, Platform.BINARY_SENSOR]
 
@@ -31,12 +34,13 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         hass.data.get(DOMAIN, {}).pop(entry.entry_id, None)
         raise
     entry.async_on_unload(unsub_relay)
-    # Remove only obsolete room forecasts belonging to this entry/platform.
+    # Remove only obsolete zone forecasts belonging to this entry/platform. Zones
+    # deleted in the UI are also removed by HA through their subentry link.
     registry = er.async_get(hass)
-    expected = {f"{entry.entry_id}_{room}_predicted_60min" for room in coordinator.rooms}
+    expected = {f"{entry.entry_id}_{zone}_predicted_60min" for zone in coordinator.rooms}
     for entity in er.async_entries_for_config_entry(registry, entry.entry_id):
         if (entity.platform == DOMAIN and
-                entity.unique_id.startswith(f"{entry.entry_id}_sensor.") and
+                entity.unique_id.startswith(f"{entry.entry_id}_") and
                 entity.unique_id.endswith("_predicted_60min") and
                 entity.unique_id not in expected):
             registry.async_remove(entity.entity_id)
@@ -62,8 +66,14 @@ async def async_remove_entry(hass: HomeAssistant, entry: ConfigEntry) -> None:
 
 
 async def async_migrate_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
-    """Migrate legacy single weather source without changing user selections."""
-    if entry.version > 2:
+    """Migrate older entries without changing the user's selections.
+
+    1 -> 2: single outdoor sensor becomes a prioritized source list.
+    2 -> 3: each room sensor becomes a one-sensor zone subentry with its comfort
+    weight. Its entity ID stays the zone key, so learned models, forecast entities
+    and accuracy statistics carry over. Older versions cannot load version 3.
+    """
+    if entry.version > 3:
         return False
     if entry.version == 1:
         def migrate(config):
@@ -76,4 +86,25 @@ async def async_migrate_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             entry, data=migrate(entry.data), options=migrate(entry.options),
             version=2, minor_version=1,
         )
+    if entry.version == 2:
+        config = {**entry.data, **entry.options}
+        rooms = [room for room in config.get(CONF_ROOMS, []) if isinstance(room, str)]
+        registry = er.async_get(hass)
+        names = {}
+        for room in rooms:
+            state, registered = hass.states.get(room), registry.async_get(room)
+            names[room] = ((state.name if state else None)
+                           or (registered.name or registered.original_name if registered else None)
+                           or room)
+        existing = {sub.unique_id for sub in entry.subentries.values()}
+        for data in legacy_zone_data(rooms, config.get(CONF_WEIGHTS), names):
+            if data[ZONE_KEY] not in existing:
+                hass.config_entries.async_add_subentry(entry, ConfigSubentry(
+                    data=MappingProxyType(data), subentry_type=SUBENTRY_ZONE,
+                    title=data[ZONE_NAME], unique_id=data[ZONE_KEY]))
+
+        def strip(config):
+            return {k: v for k, v in config.items() if k not in (CONF_ROOMS, CONF_WEIGHTS)}
+        hass.config_entries.async_update_entry(
+            entry, data=strip(entry.data), options=strip(entry.options), version=3, minor_version=1)
     return True