Resume a figure after a library rescan

play_figure resumed only when the player's playlist *was* the figure's playlist
object. rescan_library rebuilds every Playlist, so after the refresh button - or
the podcast poller landing a new episode, every few hours on its own - putting a
figure back started it over. Playlist is a frozen dataclass: compare by value.

The album picker's "keep what is already playing" check had the same identity
comparison and restarted the album after a rescan; it compares by value too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

python-backend/tests/test_web.py

@@ -199,15 +199,15 @@ async def test_play_can_start_at_a_track(client: Client, sim: Simulation) -> Non
     assert (await client.get("/api/state")).json()["track_index"] == 2
 
 
-async def test_playing_a_figure_album_reuses_the_figure_playlist(
+async def test_playing_a_figure_album_plays_the_figure_playlist(
     client: Client, sim: Simulation
 ) -> None:
-    """Identity matters: ``play_figure`` resumes on an ``is`` check."""
+    """Equal to the figure's own playlist, so placing the figure afterwards resumes it."""
     album = await album_by_title(client, "Fuchs")
     await client.post("/api/play", json={"album_id": album["id"]})
     await sim.bus.drain()
 
-    assert sim.player.playlist is sim.app.playlists["fuchs"][0]
+    assert sim.player.playlist == sim.app.playlists["fuchs"][0]
 
 
 async def test_playing_an_unknown_album_is_a_404(client: Client) -> None: