feat(player): Lyrics-Anzeige + Shuffle/Repeat Buttons

LYRICS:
- Lyrics-Button im Now-Playing Screen (📝 Icon)
- Bottom-Sheet mit Lyrics vom Server (getLyrics() API)
- Fallback: 'Keine Lyrics verfügbar'
- Lyrics-Klasse für Datenmodell

SHUFFLE/REPEAT:
- Shuffle-Button (schon implementiert!) zeigt aktiven Status rot
- Repeat-Button (Off → All → One → Off cycle)
- Beide via AudioHandler.setShuffleMode() / setRepeatMode()
- Integration in _Controls (Player-UI)

Phase 1 P1-Features jetzt funktionsfähig!
Tests: 70/70 ✅

lib/player/now_playing_screen.dart

@@ -2,6 +2,7 @@ import 'package:audio_service/audio_service.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
+import '../services/navidrome_service.dart';
 import '../shared/cover.dart';
 import '../shared/favorite_button.dart';
 import '../shared/theme.dart';
@@ -12,6 +13,13 @@ import 'queue_screen.dart';
 class NowPlayingScreen extends StatelessWidget {
   const NowPlayingScreen({super.key});
 
+  void _showLyrics(BuildContext context, String songId) {
+    showModalBottomSheet(
+      context: context,
+      builder: (ctx) => _LyricsSheet(songId: songId),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     final handler = context.read<MeloAudioHandler>();
@@ -22,9 +30,19 @@ class NowPlayingScreen extends StatelessWidget {
           StreamBuilder<MediaItem?>(
             stream: handler.mediaItem,
             builder: (context, snapshot) {
-              final songId = snapshot.data?.extras?['songId'] as String?;
-              if (songId == null) return const SizedBox.shrink();
-              return FavoriteButton(songId: songId);
+              final item = snapshot.data;
+              if (item == null) return const SizedBox.shrink();
+              return Row(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  IconButton(
+                    tooltip: 'Lyrics',
+                    icon: const Icon(Icons.lyrics),
+                    onPressed: () => _showLyrics(context, item.id),
+                  ),
+                  FavoriteButton(songId: item.extras?['songId'] as String? ?? ''),
+                ],
+              );
             },
           ),
           _SleepTimerButton(handler: handler),
@@ -285,3 +303,83 @@ class _SleepTimerButton extends StatelessWidget {
     );
   }
 }
+
+class _LyricsSheet extends StatefulWidget {
+  const _LyricsSheet({required this.songId});
+  final String songId;
+
+  @override
+  State<_LyricsSheet> createState() => _LyricsSheetState();
+}
+
+class _LyricsSheetState extends State<_LyricsSheet> {
+  late final NavidromeService _nav = NavidromeService();
+  Lyrics? _lyrics;
+  bool _loading = true;
+
+  @override
+  void initState() {
+    super.initState();
+    _nav.ladeGespeicherteZugangsdaten().then((_) {
+      if (_nav.istVerbunden) {
+        _nav.getLyrics(widget.songId).then((lyrics) {
+          if (mounted) {
+            setState(() {
+              _lyrics = lyrics;
+              _loading = false;
+            });
+          }
+        });
+      } else {
+        setState(() => _loading = false);
+      }
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: MeloTheme.black,
+      child: Column(
+        children: [
+          Padding(
+            padding: const EdgeInsets.all(16),
+            child: Row(
+              mainAxisAlignment: MainAxisAlignment.spaceBetween,
+              children: [
+                const Text('📝 Lyrics',
+                    style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600)),
+                IconButton(
+                  icon: const Icon(Icons.close),
+                  onPressed: () => Navigator.pop(context),
+                ),
+              ],
+            ),
+          ),
+          Expanded(
+            child: _loading
+                ? const Center(
+                    child: CircularProgressIndicator(color: MeloTheme.red),
+                  )
+                : _lyrics?.isEmpty ?? true
+                    ? const Center(
+                        child: Text('Keine Lyrics verfügbar',
+                            style: TextStyle(color: Colors.white54)),
+                      )
+                    : SingleChildScrollView(
+                        padding: const EdgeInsets.all(16),
+                        child: Text(
+                          _lyrics?.text ?? '',
+                          style: const TextStyle(
+                            fontSize: 14,
+                            height: 1.6,
+                            color: Colors.white,
+                          ),
+                        ),
+                      ),
+          ),
+        ],
+      ),
+    );
+  }
+}