fix: NP flicker, fully-random shuffle, playlist count backpatch

NP overlay flicker (stronger fix):
- Remove contain:layout style paint (causes layer issues on some Android WebView)
- Add ::before pseudo-element with solid background so no frame can be transparent
- Add -webkit-transform prefixes for both open and closed states

Shuffle fully random:
- playQueue no longer pins startIdx when shuffle is on
- All songs shuffled into a completely random order, S.qIdx=0 always
- toggleShuffle mid-queue still pins current song first (Spotify toggle behavior)

Playlist count wrong in overview:
- Navidrome's getPlaylists returns stale/wrong songCount in its index
- Add data-pl-id to each playlist card in loadPlaylists
- After loadPlaylistDetail gets the accurate entry count, backpatch the
  matching overview card's subtitle so the grid shows the real song count

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

src/views.js

@@ -687,6 +687,7 @@ export async function loadPlaylists() {
     lists.forEach(pl => {
       const cv = coverUrl(pl.coverArt, 512);
       const c = makeCard(pl.name, pl.songCount+' Titel', cv, '🎶');
+      c.dataset.plId = pl.id;
       c.querySelector('.card-art').onclick = (e) => { e.stopPropagation(); quickPlayPlaylist(pl); };
       c.querySelector('.card-info').onclick = () => navigate('playlist-detail', pl);
       g.appendChild(c);
@@ -728,6 +729,10 @@ export async function loadPlaylistDetail(pl) {
     const songs = full.entry || [];
     const totalMin = Math.round(songs.reduce((s,t) => s+(t.duration||0), 0) / 60);
     document.getElementById('playlist-detail-stats').textContent = `${songs.length} Titel · ${totalMin} Min.`;
+    // Navidrome's getPlaylists can return a stale songCount — backpatch the overview card
+    // with the real count we just got from getPlaylist so the grid always shows truth.
+    const overviewCard = document.querySelector(`#playlists-grid [data-pl-id="${pl.id}"]`);
+    if (overviewCard) overviewCard.querySelector('.card-sub').textContent = songs.length + ' Titel';
     const descEl = document.getElementById('playlist-detail-desc');
     if(descEl) { descEl.textContent = full.comment||''; descEl.style.display = full.comment ? '' : 'none'; }
     document.getElementById('btn-play-playlist').onclick = () => playQueue(songs, 0);