feat: renpy.call_in_new_context("_hide_windows") becomes a click wait

Ren'Py's own _hide_windows label hides the dialogue window until the player clicks. Games call it
directly between scenes, and one of them 531 times. Other labels stay unsupported.

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

backend/tests/test_renpy_universal.py

@@ -196,3 +196,12 @@ def test_compiled_image_factory_class_does_not_enter_python_init():
                  'label splashscreen:\n    jump other\n')
     audit_ir(data)
     assert any("TransitionConditionSwitch" in message for message in data.blockers)
+
+
+def test_hide_windows_context_call_is_a_click_wait():
+    data = parse('label start:\n    $ renpy.call_in_new_context("_hide_windows")\n    return\n')
+    body = data.modules["t.rpy"][0]["body"] if isinstance(data.modules, dict) else None
+    assert body and body[0]["op"] == "pause" and body[0]["d"] is None
+    assert not data.blockers
+    other = parse('label start:\n    $ renpy.call_in_new_context("something_else")\n    return\n')
+    assert other.modules["t.rpy"][0]["body"][0]["op"] == "exec"