feat(flutter): queue screen + skipToQueueItem support

- audio_handler: override skipToQueueItem(index) -> _player.seek(zero, index: i)
- player/queue_screen.dart: list of MediaItems with current track highlighted
  (left accent border + Now Playing badge), tap-to-jump on non-current rows
- /queue route + queue_music icon on /now-playing AppBar

Reorder + remove deferred for v1.

flutter_client/lib/player/now_playing_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
 
 import '../theme/theme_extension.dart';
 import 'player_provider.dart';
@@ -28,6 +29,13 @@ class NowPlayingScreen extends ConsumerWidget {
           icon: Icon(Icons.expand_more, color: fs.parchment),
           onPressed: () => Navigator.of(context).pop(),
         ),
+        actions: [
+          IconButton(
+            icon: Icon(Icons.queue_music, color: fs.parchment),
+            tooltip: 'Queue',
+            onPressed: () => GoRouter.of(context).push('/queue'),
+          ),
+        ],
       ),
       body: SafeArea(
         child: Padding(

flutter_client/lib/player/queue_screen.dart

@@ -0,0 +1,118 @@
+import 'package:audio_service/audio_service.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
+
+import '../theme/theme_extension.dart';
+import 'player_provider.dart';
+
+class QueueScreen extends ConsumerWidget {
+  const QueueScreen({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
+    final queue = ref.watch(queueProvider).value ?? const [];
+    final current = ref.watch(mediaItemProvider).value;
+    return Scaffold(
+      backgroundColor: fs.obsidian,
+      appBar: AppBar(
+        backgroundColor: fs.obsidian,
+        elevation: 0,
+        leading: IconButton(
+          icon: Icon(Icons.arrow_back, color: fs.parchment),
+          onPressed: () => context.pop(),
+        ),
+        title: Text('Queue', style: TextStyle(color: fs.parchment)),
+      ),
+      body: queue.isEmpty
+          ? Center(
+              child: Text('Queue is empty.', style: TextStyle(color: fs.ash)),
+            )
+          : ListView.separated(
+              itemCount: queue.length,
+              separatorBuilder: (_, __) => Divider(height: 1, color: fs.iron),
+              itemBuilder: (ctx, i) => _QueueRow(
+                item: queue[i],
+                index: i,
+                isCurrent: current?.id == queue[i].id,
+                onTap: () async {
+                  final h = ref.read(audioHandlerProvider);
+                  await h.skipToQueueItem(i);
+                  await h.play();
+                },
+              ),
+            ),
+    );
+  }
+}
+
+class _QueueRow extends StatelessWidget {
+  const _QueueRow({
+    required this.item,
+    required this.index,
+    required this.isCurrent,
+    required this.onTap,
+  });
+
+  final MediaItem item;
+  final int index;
+  final bool isCurrent;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
+    final dur = item.duration;
+    String? durLabel;
+    if (dur != null) {
+      final m = (dur.inSeconds ~/ 60).toString().padLeft(2, '0');
+      final s = (dur.inSeconds % 60).toString().padLeft(2, '0');
+      durLabel = '$m:$s';
+    }
+    return InkWell(
+      onTap: isCurrent ? null : onTap,
+      child: Container(
+        decoration: BoxDecoration(
+          border: isCurrent
+              ? Border(left: BorderSide(color: fs.accent, width: 2))
+              : null,
+          color: isCurrent ? fs.iron : null,
+        ),
+        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
+        child: Row(children: [
+          if (isCurrent)
+            Padding(
+              padding: const EdgeInsets.only(right: 8),
+              child: Icon(Icons.graphic_eq, color: fs.accent, size: 16),
+            ),
+          Expanded(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Text(
+                  item.title,
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                  style: TextStyle(
+                    color: isCurrent ? fs.accent : fs.parchment,
+                    fontSize: 14,
+                    fontWeight: isCurrent ? FontWeight.w500 : FontWeight.w400,
+                  ),
+                ),
+                Text(
+                  '${item.artist ?? ''} · ${item.album ?? ''}',
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                  style: TextStyle(color: fs.ash, fontSize: 12),
+                ),
+              ],
+            ),
+          ),
+          if (durLabel != null)
+            Text(durLabel, style: TextStyle(color: fs.ash, fontSize: 12)),
+        ]),
+      ),
+    );
+  }
+}

flutter_client/lib/shared/routing.dart

@@ -11,6 +11,7 @@ import '../library/home_screen.dart';
 import '../library/library_screen.dart';
 import '../player/now_playing_screen.dart';
 import '../player/player_bar.dart';
+import '../player/queue_screen.dart';
 import '../playlists/playlist_detail_screen.dart';
 import '../playlists/playlists_list_screen.dart';
 import '../search/search_screen.dart';
@@ -55,6 +56,7 @@ GoRouter buildRouter(Ref ref) {
             builder: (_, s) => AlbumDetailScreen(id: s.pathParameters['id']!),
           ),
           GoRoute(path: '/now-playing', builder: (_, __) => const NowPlayingScreen()),
+          GoRoute(path: '/queue', builder: (_, __) => const QueueScreen()),
           GoRoute(path: '/search', builder: (_, __) => const SearchScreen()),
           GoRoute(path: '/library', builder: (_, __) => const LibraryScreen()),
           GoRoute(path: '/playlists', builder: (_, __) => const PlaylistsListScreen()),