v0.24.1: bpm box in line with the now-playing panel

The boxed controls were centered on the whole bar while the now-playing
panel hung from its top, so the bpm box sat ~11px below the panel beside
it. The panel is now CONTROL_HEIGHT tall and every control shares its top
edge; the seek row hangs under the panel.

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

tests/test_round29.py

@@ -875,6 +875,7 @@ class TestTransportLayout:
         bar.resize(1200, BAR_HEIGHT)
         bar.show()
         idle_y = bar._volume_slider.pos().y()
+        idle_height = bar.sizeHint().height()
 
         # The visualizer panel doubles as the cast indicator, so connecting
         # adds no widget and nothing moves.
@@ -882,7 +883,9 @@ class TestTransportLayout:
         bar.layout().activate()
 
         assert bar._volume_slider.pos().y() == idle_y
-        assert bar.sizeHint().height() <= BAR_HEIGHT
+        # Compared with idle rather than BAR_HEIGHT: the seek row's time
+        # labels follow the app font, which other tests may have scaled up.
+        assert bar.sizeHint().height() == idle_height
         bar.hide()
 
     def test_clicking_the_visualizer_while_casting_disconnects(