Clean up shared UI runtime state

run-headless.sh

@@ -18,7 +18,7 @@
 # `content_scale` 2.55, from docs/bench/iris-phone-v2-2026-09-06.md,
 # carried in `ai_app::ui::fixture::PHONE_*`), and `IRIS_SCALE` hands that
 # density to iris the way `DisplayMetrics.density` does on Android
-# (`iris::default::content_scale`). So a screenshot from here and one
+# (`iris::desktop::content_scale`). So a screenshot from here and one
 # from the phone are the same layout at the same density, and what
 # differs is only the renderer. Without it the output stays desktop-
 # shaped, which is what every other example wants.