perf: smooth UI animations and reduce repaint overhead

Batch of performance and animation work: shared FadeHelper/MotionPrefs
primitives, hover animators, shadow pixmap caching, smooth scrolling,
seek time bubble, and widespread component repaint reductions.

src/qEmbyApp/components/serverwheelview.cpp

@@ -10,6 +10,8 @@
 #include <QLabel>
 #include <QPushButton>
 #include <QFont>
+#include "../tokens/AnimationTokens.h"
+#include "../utils/motionprefs.h"
 
 ServerWheelView::ServerWheelView(QWidget* parent) : QWidget(parent) {
     setAttribute(Qt::WA_StyledBackground, true);
@@ -17,8 +19,8 @@ ServerWheelView::ServerWheelView(QWidget* parent) : QWidget(parent) {
 
     m_scrollAnim = new QVariantAnimation(this);
     
-    m_scrollAnim->setEasingCurve(QEasingCurve::OutExpo);
-    m_scrollAnim->setDuration(450);
+    m_scrollAnim->setEasingCurve(AnimationTokens::Curve::enter());
+    m_scrollAnim->setDuration(AnimationTokens::DurationMs::kSlow);
     connect(m_scrollAnim, &QVariantAnimation::valueChanged, this, [this](const QVariant& val){
         m_scrollOffset = val.toReal();
         updateLayout();
@@ -186,6 +188,11 @@ void ServerWheelView::installFilterRecursively(QWidget* w) {
 
 void ServerWheelView::scrollTo(qreal target) {
     m_scrollAnim->stop();
+    if (MotionPrefs::reduceMotion()) {
+        m_scrollOffset = target;
+        updateLayout();
+        return;
+    }
     m_scrollAnim->setStartValue(m_scrollOffset);
     m_scrollAnim->setEndValue(target);
     m_scrollAnim->start();