fix: observe playback state to unhide native video surface

Checks/app-startup.py

@@ -285,8 +285,15 @@ def check_cli_instances(root, app, fixtures):
                             and state["position"] > 0 and state["hasVideo"] for state in states.values()),
                             "cold default CLI opens one actual player window")
         first_pid = next(iter(first))
+        renderer = first[first_pid]["window"]
+        if (not renderer.get("rendererAttached") or renderer.get("rendererHidden")
+                or abs(renderer["rendererWidth"] - renderer["videoWidth"]) > 1
+                or abs(renderer["rendererHeight"] - renderer["videoHeight"]) > 1):
+            raise RuntimeError(f"playing renderer must fill its visible native surface: {renderer}")
         opened = input_request(first_pid, 1, lambda state: state["showsQueue"]
                                and state["window"].get("videoOwnsMouse") is True
+                               and state["window"].get("rendererAttached") is True
+                               and state["window"].get("rendererHidden") is False
                                and abs(state["window"]["videoWidth"] - first[first_pid]["window"]["videoWidth"]) < 1,
                                "queue preserves video size and mouse target", action="queue", visible=True)
         window = opened[first_pid]["window"]