feat: player drag feedback, global search fixes, iTunes artist discovery

- Player bar: drag handle pill + live lift/peek animation when swiping up to NP
- Global search: now includes Navidrome library results alongside iTunes; fix songs not showing (filter wrapperType=track)
- iTunes artist page: hero banner with album art, top songs section
- Artist detail: iTunes global top tracks + extra albums not on server

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

index.html

@@ -307,6 +307,7 @@
 
   <!-- PLAYER -->
   <div class="player">
+    <div class="player-drag-handle"></div>
     <div class="player-track">
       <div class="player-art" id="player-art" style="cursor:pointer" title="Jetzt läuft öffnen"><div class="no-art">♪</div></div>
       <div class="player-info">