Extends the shared-element morph across a real route change. Mount it once beside your other providers, put a DrylMorph with the same Name on both pages, and the object the user pressed travels with them. It never intercepts or restarts a navigation, so the history stack and the Back button are untouched. Timeout bounds how long the old frame may be held when a destination never reports a render; ShouldMorph excludes individual navigations.