feat: notification nav + ABS search + HTML desc fix + brighter NowPlaying bg

- Notification sheet: add 'Zum Album →' / 'Öffnen →' button; tapping searches
  Navidrome and navigates to the matching album/playlist
- AppNotification: add navType/navAlbum/navArtist/navId fields (mirrors web notify.js)
- ImporterViewModel: store resolved album/artist/type in notification after download
- ABS Android: search bar with 400ms debounce, server-side search via /search endpoint
- AbsClient: add searchLibraryItems() for library-specific search
- AbsScreen/abs.js: strip HTML tags from book descriptions (<p> tags no longer visible)
- NowPlayingScreen: vibrant palette swatch + lighter scrim (0.15) + wider gradient
  for more visible dominant color background

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/src/main/AndroidManifest.xml

@@ -43,6 +43,7 @@
             </intent-filter>
         </service>
 
+
         <!-- Android Auto -->
         <meta-data
             android:name="com.google.android.gms.car.application"