fix: sync editor playhead with selection changes

tests/test_ui_structure.py

@@ -1158,6 +1158,37 @@ def test_editor_playhead_change_keeps_looping_when_inside_selection(win, tmp_pat
     assert stopped["n"] == 0
 
 
+def test_editor_selection_change_moves_playhead_to_area_start(win, tmp_path):
+    import main as m
+    src = tmp_path / "v0.wav"; src.write_bytes(b"")
+    dlg = m.AudioEditorDialog(str(src), parent=win)
+    dlg._clip_dur = 6.0
+    dlg._wave.set_view(0.0, 6.0)
+    dlg._wave.set_playhead(5.0)
+    dlg._on_wave_selection_changed(1.5, 3.5)
+    assert dlg._wave.playhead() == 1.5
+
+
+def test_editor_selection_change_updates_active_loop_bounds(win, tmp_path, monkeypatch):
+    import main as m
+    src = tmp_path / "v0.wav"; src.write_bytes(b"")
+    dlg = m.AudioEditorDialog(str(src), parent=win)
+    dlg._clip_dur = 6.0
+    dlg._wave.set_view(0.0, 6.0)
+    dlg._wave.set_selection(1.0, 3.0)
+    dlg._wave.set_playhead(2.0)
+    dlg._play_proc = object()
+    dlg._play_loop = True
+    seen = {}
+    monkeypatch.setattr(
+        dlg, "_play_current",
+        lambda start=None, end=None, loop=False:
+            seen.update(start=start, end=end, loop=loop))
+    dlg._on_wave_selection_changed(1.0, 4.0)
+    assert seen == {"start": 1.0, "end": 4.0, "loop": True}
+    assert dlg._wave.playhead() == 1.0
+
+
 def test_editor_has_local_speed_controls(win, tmp_path):
     import main as m
     from PyQt6.QtWidgets import QPushButton