feat(scrobble stats): navigator lower bound, clickable rows, android button to top

- Navigator can't step before logging began: the endpoint returns firstPlayedAt
  (MIN(played_at) over all the user's plays, unfiltered by window); web + android
  disable the back arrow once the shown year/month is at/before that first play.
- Top artists/tracks/albums are now clickable → open the artist / album page (web
  navigates and closes the overlay; android navigates via nav routes). Tracks open
  their album.
- Android: moved the 'Meine Statistiken' button to the top of Settings (was at the
  bottom near logout). SW cache -> ns-v70.

Android compileDebugKotlin + web build green; firstPlayedAt verified server-side.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui/stats.js

@@ -14,6 +14,7 @@ let _overlay = null;
 let _view  = 'all';                 // all | year | month
 let _year  = new Date().getFullYear();
 let _month = new Date().getMonth();  // 0-11
+let _firstPlayedAt = null;           // epoch secs of the user's earliest play → navigator lower bound
 
 const _MONTHS = ['Januar', 'Februar', 'März', 'April', 'Mai', 'Juni',
                  'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'];
@@ -64,6 +65,15 @@ function _atCurrent() {
   return true;
 }
 
+// True when the shown period is at/before the user's first logged play — caps stepping backwards.
+function _atStart() {
+  if (!_firstPlayedAt) return false;
+  const f = new Date(_firstPlayedAt * 1000);
+  if (_view === 'year')  return _year <= f.getFullYear();
+  if (_view === 'month') return _year < f.getFullYear() || (_year === f.getFullYear() && _month <= f.getMonth());
+  return false;
+}
+
 function _step(dir) {
   if (_view === 'year') { _year += dir; }
   else if (_view === 'month') {
@@ -101,6 +111,16 @@ function _buildOverlay() {
       <div class="stats-tabs" id="stats-tabs" style="display:flex;gap:6px;padding:12px 18px 0"></div>
       <div class="stats-body" id="stats-body" style="padding:16px 18px;overflow-y:auto"></div>
     </div>`;
+  // Delegated navigation: click an artist / album / track row → open its page.
+  _overlay.querySelector('#stats-body').addEventListener('click', async e => {
+    const row = e.target.closest('[data-nav-type]');
+    if (!row) return;
+    const { navType, navId, navName, navArtist } = row.dataset;
+    closeStats();
+    const { navigate } = await import('../views/views.js');
+    if (navType === 'artist') navigate('artist-detail', { id: navId, name: navName });
+    else if (navType === 'album') navigate('album-detail', { id: navId, name: navName, artist: navArtist || '' });
+  });
   document.body.appendChild(_overlay);
   _renderTabs();
 }
@@ -121,7 +141,7 @@ function _renderTabs() {
              font-size:16px;line-height:1;display:flex;align-items:center;justify-content:center">${label}</button>`;
   const stepper = _view === 'all' ? '' : `
     <div style="display:flex;align-items:center;gap:8px;margin-left:auto">
-      ${stepBtn(-1, '‹', false)}
+      ${stepBtn(-1, '‹', _atStart())}
       <div style="min-width:118px;text-align:center;font-weight:700;font-size:14px">${esc(_periodLabel())}</div>
       ${stepBtn(1, '›', _atCurrent())}
     </div>`;
@@ -153,6 +173,7 @@ async function _load() {
     const res = await fetch(`${S.cfg.scrobbleUrl}/scrobble/stats?${qs}`);
     if (!res.ok) { body.innerHTML = _errBox(`Fehler ${res.status}`); return; }
     const d = await res.json();
+    if (d.firstPlayedAt) { _firstPlayedAt = d.firstPlayedAt; _renderTabs(); }  // apply back-bound
     _render(body, d);
   } catch {
     body.innerHTML = _errBox('Scrobble-Dienst nicht erreichbar.');
@@ -172,9 +193,12 @@ function _render(body, d) {
   body.innerHTML = [
     _tiles(d),
     _seriesChart(d.series, d.range.bucket),
-    _topList('Top-Künstler', d.topArtists, a => a.name, a => a.plays, a => a.artistId, true),
-    _topList('Top-Songs', d.topTracks, t => `${t.title}${t.artist ? ' · ' + t.artist : ''}`, t => t.plays, t => t.coverArt || t.albumId || t.songId),
-    _topList('Top-Alben', d.topAlbums, a => `${a.name}${a.artist ? ' · ' + a.artist : ''}`, a => a.plays, a => a.coverArt || a.albumId),
+    _topList('Top-Künstler', d.topArtists, a => a.name, a => a.plays, a => a.artistId, true,
+      a => a.artistId ? { type: 'artist', id: a.artistId, name: a.name } : null),
+    _topList('Top-Songs', d.topTracks, t => `${t.title}${t.artist ? ' · ' + t.artist : ''}`, t => t.plays, t => t.coverArt || t.albumId || t.songId, false,
+      t => t.albumId ? { type: 'album', id: t.albumId, name: t.album, artist: t.artist } : null),
+    _topList('Top-Alben', d.topAlbums, a => `${a.name}${a.artist ? ' · ' + a.artist : ''}`, a => a.plays, a => a.coverArt || a.albumId, false,
+      a => a.albumId ? { type: 'album', id: a.albumId, name: a.name, artist: a.artist } : null),
     _hourClock(d.byHour),
   ].join('');
 }
@@ -210,7 +234,7 @@ function _seriesChart(series, bucket) {
     <div style="display:flex;gap:3px;align-items:flex-end;margin:6px 0 24px;overflow-x:auto;padding-bottom:8px">${bars}</div>`;
 }
 
-function _topList(title, items, labelFn, valFn, idFn = null, circular = false) {
+function _topList(title, items, labelFn, valFn, idFn = null, circular = false, navFn = null) {
   if (!items?.length) return '';
   const max = Math.max(...items.map(valFn), 1);
   const radius = circular ? '50%' : '6px';
@@ -220,7 +244,11 @@ function _topList(title, items, labelFn, valFn, idFn = null, circular = false) {
     const thumb = `<div style="width:40px;height:40px;border-radius:${radius};background:var(--surface2);flex-shrink:0;overflow:hidden">
         ${cover ? `<img src="${esc(cover)}" loading="lazy" style="width:100%;height:100%;object-fit:cover" onerror="this.style.display='none'">` : ''}
       </div>`;
-    return `<div style="display:flex;align-items:center;gap:10px;padding:6px 0">
+    const nav = navFn ? navFn(it) : null;
+    const navAttrs = nav
+      ? `data-nav-type="${nav.type}" data-nav-id="${esc(nav.id)}" data-nav-name="${esc(nav.name || '')}" data-nav-artist="${esc(nav.artist || '')}"`
+      : '';
+    return `<div ${navAttrs} style="display:flex;align-items:center;gap:10px;padding:6px 0${nav ? ';cursor:pointer' : ''}">
       <div style="width:18px;text-align:right;color:var(--text2);font-size:13px;font-weight:700">${i + 1}</div>
       ${thumb}
       <div style="flex:1;min-width:0">