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>

src/views/abs.js

@@ -2,6 +2,12 @@ import { S } from '../state.js';
 import { esc, toast } from '../utils.js';
 import { cancelMusicAutoplay } from '../player/player.js';
 
+function stripHtml(html) {
+  const div = document.createElement('div');
+  div.innerHTML = html;
+  return (div.textContent || div.innerText || '').trim();
+}
+
 // ─── HTTP HELPERS ───
 // API calls are routed through the NovaSonic backend proxy to avoid CORS restrictions.
 // Audio streaming uses <audio src> directly (HTML media elements bypass CORS).
@@ -609,7 +615,7 @@ export async function loadAbsBookDetail(itemId) {
           </button>
         </div>
       </div>
-      ${meta.description ? `<div class="abs-detail-desc">${esc(meta.description)}</div>` : ''}
+      ${meta.description ? `<div class="abs-detail-desc">${esc(stripHtml(meta.description))}</div>` : ''}
       ${chapters.length ? `
         <div class="abs-detail-chapters">
           <h3 class="abs-detail-chapters-title">Kapitel <span class="abs-ch-count">${chapters.length}</span></h3>