feat: improve RenPy conversion and support MIST runtime

backend/tests/test_screens.py

@@ -89,9 +89,9 @@ def test_shown_screens_are_audited_but_unshown_ones_are_not():
 
 
 def test_unknown_actions_and_screens_block_the_import():
-    data = parse('screen s():\n    textbutton "x" action Preference("fullscreen")\nlabel start:\n    call screen s\n')
+    data = parse('screen s():\n    textbutton "x" action UnsupportedAction("fullscreen")\nlabel start:\n    call screen s\n')
     audit_ir(data)
-    with pytest.raises(CompatibilityError, match="Preference"):
+    with pytest.raises(CompatibilityError, match="UnsupportedAction"):
         require_supported_scripts(data)
     data = parse('label start:\n    call screen nowhere\n')
     audit_ir(data)