Expose battery maintenance status (e.g. replace_now) as a sensor

Some battery devices report a full battery level while still signalling that
the battery must be replaced (the customer's log shows devices at lvl 100 with
state "replace_now"). That maintenance state was not surfaced anywhere.

When the battery service supports the replace_* events (per its `sup_events`
property), expose the hub-reported `state` attribute as a diagnostic
"Battery status" sensor.

futurehome/CHANGELOG.md

@@ -1,5 +1,9 @@
 <!-- https://developers.home-assistant.io/docs/add-ons/presentation#keeping-a-changelog -->
 
+## 1.8.0 (01.07.2026)
+
+- Expose the battery maintenance status (e.g. `replace_now`) as a diagnostic "Battery status" sensor for devices that support the `replace_*` battery events. Previously this was not surfaced at all, so a device could report a full battery level while actually needing its battery replaced.
+
 ## 1.7.0 (01.07.2026)
 
 - Added support for the Futurehome house mode (Home/Away/Sleep/Vacation). The current mode is exposed as a `Mode` selector on the Smarthub device, updates in real time (e.g. when a Futurehome Modeswitch button is pressed), and can be changed from Home Assistant.

futurehome/config.yaml

@@ -1,6 +1,6 @@
 # https://developers.home-assistant.io/docs/add-ons/configuration#add-on-config
 name: Futurehome
-version: '1.7.0'
+version: '1.8.0'
 slug: futurehome
 description: Local Futurehome Smarthub integration
 url: 'https://github.com/adrianjagielak/home-assistant-futurehome'

futurehome/src/services/battery.ts

@@ -32,6 +32,26 @@ export function battery__components(
     };
   }
 
+  // Battery maintenance status (e.g. "replace_now"). A device can report a full
+  // battery level while still asking to be replaced, so when it supports the
+  // replace_* events this is surfaced as its own diagnostic sensor. The hub
+  // reports the current state as a plain string in the `state` attribute.
+  const supEvents: string[] = svc.props?.sup_events ?? [];
+  if (
+    supEvents.some(
+      (event) => typeof event === 'string' && event.startsWith('replace'),
+    )
+  ) {
+    components[`${svc.addr}_state`] = {
+      unique_id: `${svc.addr}_state`,
+      platform: 'sensor',
+      entity_category: 'diagnostic',
+      icon: 'mdi:battery-heart-variant',
+      name: 'Battery status',
+      value_template: `{{ value_json['${svc.addr}'].state | default('ok', true) }}`,
+    };
+  }
+
   return {
     components: components,
   };