Ajoute l'overlay Qt, pour les plateformes sans Cocoa

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_interface.py

@@ -14,3 +14,15 @@ def test_une_plateforme_inconnue_est_refusee_clairement():
     with pytest.raises(NotImplementedError) as e:
         classe_overlay_pour("haiku-os")
     assert "haiku-os" in str(e.value)
+
+
+def test_la_fabrique_rend_overlayqt_pour_win32():
+    classe = classe_overlay_pour("win32")
+    from interface.qt import OverlayQt
+    assert classe is OverlayQt
+
+
+def test_l_overlay_qt_declare_tout_le_contrat():
+    classe = classe_overlay_pour("win32")
+    for methode in ("show", "hide", "set_level", "set_status", "rearmer_garde"):
+        assert callable(getattr(classe, methode, None)), f"{methode} manque"