perf(dashboard): stop animating the live EPG progress fills

A live-EPG tick moves the bar by under one percent, so the 0.4 s transform
transition was invisible but still produced a burst of compositor frames
on every tick. Place the fill without a transition.

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

.changes/dashboard-live-progress-compositor.md

@@ -3,6 +3,6 @@ type: perf
 area: dashboard
 ---
 
-Live programme progress bars on the dashboard now advance without redrawing
-the whole page, so a dashboard left open with recent live channels uses less
-CPU and GPU.
+Live programme progress bars on the dashboard now move without animating or
+redrawing the whole page, so a dashboard left open with recent live channels
+uses less CPU and GPU.

libs/workspace/dashboard/feature/src/lib/rails/dashboard-rail.component.scss

@@ -731,15 +731,11 @@
         height: 100%;
         background: var(--app-live-color, #ff8f8f);
         border-radius: 2px;
-        // A full-width fill slid into view, not an animated width: the
-        // transform transition runs on the compositor, so each live-EPG tick
-        // no longer re-lays out the whole page for every transition frame.
+        // A full-width fill slid into place, neither a width nor animated: a
+        // live-EPG tick moves it by under one percent, so an animation was
+        // invisible yet cost a layout pass (width) or a burst of compositor
+        // frames (transform transition) on every tick.
         transform: translateX(calc(var(--live-progress, 0) * 1% - 100%));
-        transition: transform 0.4s ease;
-
-        @media (prefers-reduced-motion: reduce) {
-            transition: none;
-        }
     }
 
     &--idle i {