[frontend] Accept tl_track in track_playback_started

Mopidy's CoreListener calls track_playback_started(tl_track=...), but the
method took a positional `track`, so every playback start raised
TypeError and the smart queue never refilled on track changes. Add a
regression test.

src/mopidy_smartplaylists/frontend.py

@@ -14,6 +14,8 @@ from mopidy_smartplaylists.generators import (
 )
 
 if TYPE_CHECKING:
+    from mopidy.models import TlTrack
+
     from mopidy_smartplaylists.compat import Config, CoreProxy, Uri
 
 logger = logging.getLogger(__name__)
@@ -63,7 +65,8 @@ class SmartPlaylistsFrontend(pykka.ThreadingActor, CoreListener):
             logger.info("Smart playlists loaded, running refresh...")
             refresh_smart_playlists(self.core, section)
 
-    def track_playback_started(self, track) -> None:
+    def track_playback_started(self, tl_track: TlTrack | None = None) -> None:
+        logger.debug("Track playback started: %s", tl_track)
         self._refill_queue()
 
     def tracklist_changed(self) -> None:

tests/test_frontend.py

@@ -74,3 +74,16 @@ class TestSmartPlaylistsFrontend:
         frontend.playlists_loaded()
 
         core.library.search.assert_not_called()
+
+    def test_track_playback_started_accepts_tl_track(self):
+        config = mock.Mock()
+        config.get.return_value = {
+            "playlist_prefix": "[Smart]",
+            "smart_queue_enabled": "false",
+        }
+        core = mock.Mock()
+
+        frontend = SmartPlaylistsFrontend(config, core)
+        frontend.track_playback_started(tl_track=mock.Mock())
+
+        core.tracklist.add.assert_not_called()