Use analytic springs and instrument resize barriers

Share a stable damped oscillator solver across scalar and rectangle animations while preserving retarget and explicit no-crossing presentation policies. Add deterministic traces, scrolling and zoom continuity coverage, and pause-aware advancement.

Measure resize barrier and handoff timing behind resize-metrics, expose the feature through the release installer, and wait for the intended backend in isolated portal tests.

compositor/src/backends/direct.rs

@@ -660,6 +660,7 @@ pub(crate) fn sleep_locked_outputs(state: &mut Ferese) {
 }
 
 pub(crate) fn wake_locked_outputs(state: &mut Ferese) {
+    state.reset_animation_clock();
     if let Some(backend) = state.direct_backend.as_mut() {
         for device in backend.devices.values_mut() {
             for output in device.outputs.values_mut() {