fix: Set Home Assistant entity categories config and diagnostic a…

…ccording to expose categories (#20663)

* Add exposes starting with 'config' or 'diagnostic' to respective Home Assistant categories

* alt proposal: default category based on new Expose property

* Use single category 'system' instead of 'config' and 'diagnostic'

* Revert "Use single category 'system' instead of 'config' and 'diagnostic'"

This reverts commit 416dd9c.

* lint

lib/extension/homeassistant.ts

@@ -1039,6 +1039,14 @@ export default class HomeAssistant extends Extension {
             throw new Error(`Unsupported exposes type: '${firstExpose.type}'`);
         }
 
+        // Exposes with category 'config' or 'diagnostic' are always added to the respective category.
+        // This takes precedence over definitions in this file.
+        if (firstExpose.category === 'config') {
+            discoveryEntries.forEach((d) => d.discovery_payload.entity_category = 'config');
+        } else if (firstExpose.category === 'diagnostic') {
+            discoveryEntries.forEach((d) => d.discovery_payload.entity_category = 'diagnostic');
+        }
+
         discoveryEntries.forEach((d) => {
             // If a sensor has entity category `config`, then change
             // it to `diagnostic`. Sensors have no input, so can't be configured.