Add album metadata attributes to Album ID sensor

Add asset_count, last_updated, and created_at attributes to the
Album ID sensor for convenient access to album metadata.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

custom_components/immich_album_watcher/sensor.py

@@ -24,6 +24,7 @@ from homeassistant.util import slugify
 
 from .const import (
     ATTR_ALBUM_ID,
+    ATTR_ALBUM_NAME,
     ATTR_ALBUM_PROTECTED_URL,
     ATTR_ALBUM_URLS,
     ATTR_ASSET_COUNT,
@@ -1211,7 +1212,10 @@ class ImmichAlbumIdSensor(ImmichAlbumBaseSensor):
             return {}
 
         attrs: dict[str, Any] = {
-            "album_name": self._album_data.name,
+            ATTR_ALBUM_NAME: self._album_data.name,
+            ATTR_ASSET_COUNT: self._album_data.asset_count,
+            ATTR_LAST_UPDATED: self._album_data.updated_at,
+            ATTR_CREATED_AT: self._album_data.created_at,
         }
 
         # Primary share URL (prefers public, falls back to protected)