feat: 'Prefer reduced motion' setting (accessibility / animation opt-out)

Config::reducedMotion (default false = playful animations ON). Surfaced as a
checkbox on first run (wizard PageMenu) and in Settings → Appearance —
unchecked by default, matching the OS 'Reduce Motion' convention. The mining
tab's AnimatedImages now freeze when it's set (MiningBackend exposes it to
mining.qml). Foundation for gating the ambient silliness to come.

src/widgets/MiningWidget.cpp

@@ -11,6 +11,8 @@
 #include <QThread>
 #include <QDateTime>
 
+#include "utils/config.h"
+
 static QString formatUptime(qint64 secs) {
     return QString("%1:%2:%3")
         .arg(secs / 3600, 2, 10, QChar('0'))
@@ -29,6 +31,7 @@ MiningWidget::MiningWidget(Wallet *wallet, QWidget *parent)
     layout->setContentsMargins(0, 0, 0, 0);
     layout->addWidget(m_quickWidget);
 
+    m_backend->setReducedMotion(conf()->get(Config::reducedMotion).toBool());
     m_quickWidget->rootContext()->setContextProperty("mining", m_backend);
     m_quickWidget->setResizeMode(QQuickWidget::SizeRootObjectToView);
     m_quickWidget->setSource(QUrl("qrc:/qml/mining.qml"));

src/widgets/MiningWidget.h

@@ -15,13 +15,17 @@
 class MiningBackend : public QObject {
 Q_OBJECT
     Q_PROPERTY(int daemonMiningState READ daemonMiningState NOTIFY daemonMiningStateChanged)
+    Q_PROPERTY(bool reducedMotion READ reducedMotion NOTIFY reducedMotionChanged)
 public:
     explicit MiningBackend(QObject *parent = nullptr) : QObject(parent) {}
     int daemonMiningState() const { return m_state; }
     void setState(int s) { if (m_state != s) { m_state = s; emit daemonMiningStateChanged(); } }
+    bool reducedMotion() const { return m_reducedMotion; }
+    void setReducedMotion(bool r) { if (m_reducedMotion != r) { m_reducedMotion = r; emit reducedMotionChanged(); } }
 
 signals:
     void daemonMiningStateChanged();
+    void reducedMotionChanged();
     void daemonOutput(const QString &line);
     void syncStatus(int from, int to, int pct);
     void uptimeChanged(const QString &uptime);
@@ -29,6 +33,7 @@ signals:
 
 private:
     int m_state = 0;   // 0:idle 1:startup 2:syncing 3:mining
+    bool m_reducedMotion = false;
 };
 
 // wowlet: the pixel-art mining tab. Hosts mining.qml and wires its pick-axe to the wallet's solo