Enhance CSS animations and performance across seasonal styles; add will-change property for smoother transitions and optimize keyframes. [skip ci]

Jellyfin.Plugin.Seasonals/Web/earthday.css

@@ -7,9 +7,11 @@
     pointer-events: none;
     z-index: 1000;
     overflow: hidden;
+    contain: layout paint;
 }
 
 .earthday-meadow {
+    will-change: transform;
     position: absolute;
     bottom: 0;
     left: 0;
@@ -25,6 +27,7 @@
 }
 
 .earthday-sway {
+    will-change: transform;
     transform-origin: bottom center;
     animation: sway-grass 4s ease-in-out infinite alternate;
 }