chatgui: rlottie animated emoji with hover-to-animate, drag-to-select

- Add LottieIcon class (TGS gzip decompress + rlottie C API render)
- Add AnimTimer singleton (33ms tick, activate/deactivate refcount)
- Add EmojiButton (hover-triggered animation in emoji picker)
- Add AnimatedEmoji support to EmojiData (5 TGS mappings)
- MessageDelegate: QTextLayout-based animated emoji overlay (text + reactions)
- ChatView: drag-to-select (click deselects, 5px drag starts selection)
- ChatView: hoveredIndexChanged signal for hover-triggered animations
- MessageList: wire AnimTimer tick to viewport update, hover → activate
- CMake: AUTORCC, rlottie, zlib dependencies
- Add 5 TGS animations as Qt resources

tools/chatgui/src/animtimer.cpp

@@ -0,0 +1,44 @@
+#include "animtimer.h"
+#include "lottieicon.h"
+
+AnimTimer::AnimTimer() {
+    m_timer.setInterval(33);
+    connect(&m_timer, &QTimer::timeout, this, &AnimTimer::onTimer);
+    m_timer.start();
+}
+
+AnimTimer *AnimTimer::instance() {
+    static AnimTimer s;
+    return &s;
+}
+
+void AnimTimer::registerIcon(const QString &key, LottieIcon *icon) {
+    m_icons.insert(key, icon);
+}
+
+void AnimTimer::unregisterIcon(const QString &key) {
+    m_icons.remove(key);
+}
+
+LottieIcon *AnimTimer::icon(const QString &key) const {
+    return m_icons.value(key, nullptr);
+}
+
+void AnimTimer::activate() {
+    if (m_activeRef++ == 0) {
+        for (auto *icon : m_icons)
+            icon->advanceFrame();
+        emit ticked();
+    }
+}
+
+void AnimTimer::deactivate() {
+    if (m_activeRef > 0) m_activeRef--;
+}
+
+void AnimTimer::onTimer() {
+    if (m_activeRef <= 0) return;
+    for (auto *icon : m_icons)
+        icon->advanceFrame();
+    emit ticked();
+}