fix(flutter): CI analyze + center title in full player

- artist_detail_screen.dart missed an `import '../models/artist.dart'`
  for the ArtistRef seed parameter; analyze flagged undefined_class.
- radio.dart + player_provider.dart doc comments wrapped URL
  parameters in <...> which lint reads as HTML. Switched to backticks.

Full player title is now centered absolutely via a Stack: title with
horizontal padding equal to the actions cluster width sits at the
optical center, while LikeButton + TrackActionsButton are pinned to
the right edge with Positioned. Fixed-height SizedBox(32) keeps the
row stable when the title wraps to a single ellipsized line.

flutter_client/lib/player/now_playing_screen.dart

@@ -219,30 +219,49 @@ class _TitleRow extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Row(children: [
-      Expanded(
-        child: Text(
-          media.title,
-          style: TextStyle(color: fs.parchment, fontSize: 22),
-          maxLines: 1,
-          overflow: TextOverflow.ellipsis,
-        ),
+    // Stack: title centered absolutely in the row; like + kebab pinned
+    // to the right edge. Padding on the title equals the actions' width
+    // so it stays optically centered without colliding with them.
+    return SizedBox(
+      height: 32,
+      child: Stack(
+        alignment: Alignment.center,
+        children: [
+          Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 64),
+            child: Text(
+              media.title,
+              style: TextStyle(color: fs.parchment, fontSize: 22),
+              maxLines: 1,
+              overflow: TextOverflow.ellipsis,
+              textAlign: TextAlign.center,
+            ),
+          ),
+          Positioned(
+            right: 0,
+            child: Row(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                LikeButton(kind: LikeKind.track, id: media.id, size: 22),
+                TrackActionsButton(
+                  track: TrackRef(
+                    id: media.id,
+                    title: media.title,
+                    albumId: (media.extras?['album_id'] as String?) ?? '',
+                    albumTitle: media.album ?? '',
+                    artistId: (media.extras?['artist_id'] as String?) ?? '',
+                    artistName: media.artist ?? '',
+                    durationSec: media.duration?.inSeconds ?? 0,
+                    streamUrl: '',
+                  ),
+                  hideQueueActions: true,
+                ),
+              ],
+            ),
+          ),
+        ],
       ),
-      LikeButton(kind: LikeKind.track, id: media.id, size: 22),
-      TrackActionsButton(
-        track: TrackRef(
-          id: media.id,
-          title: media.title,
-          albumId: (media.extras?['album_id'] as String?) ?? '',
-          albumTitle: media.album ?? '',
-          artistId: (media.extras?['artist_id'] as String?) ?? '',
-          artistName: media.artist ?? '',
-          durationSec: media.duration?.inSeconds ?? 0,
-          streamUrl: '',
-        ),
-        hideQueueActions: true,
-      ),
-    ]);
+    );
   }
 }
 

flutter_client/lib/player/player_provider.dart

@@ -104,7 +104,7 @@ class PlayerActions {
     await _ref.read(audioHandlerProvider).setVolume(v);
   }
 
-  /// Fetches /api/radio?seed_track=<id> and starts playing the
+  /// Fetches `/api/radio?seed_track=<id>` and starts playing the
   /// returned track list (seed at index 0 + recommended picks).
   Future<void> startRadio(String trackId) async {
     final dio = await _ref.read(dioProvider.future);