chatgui: proper animation shutdown + TerminateProcess for rlottie threads

- AnimTimer::shutdown(): stop QTimer, clear m_icons before icon destruction
- ~MainWindow: AnimTimer::shutdown() -> cleanupAnimations() (correct order)
- main: replace ExitProcess with TerminateProcess(GetCurrentProcess,0)
  TerminateProcess skips DLL_PROCESS_DETACH, avoiding libwinpthread
  pthread_join hang on rlottie/miniaudio threads.
  rlottie C API has no global shutdown - internal RleTaskScheduler threads
  cannot be stopped through public API. Same for miniaudio WASAPI threads.
  All owned resources already freed before TerminateProcess.

tools/chatgui/src/animtimer.cpp

@@ -1,5 +1,6 @@
 #include "animtimer.h"
 #include "lottieicon.h"
+#include "../../lib/debug_config.h"
 
 AnimTimer::AnimTimer() {
     m_timer.setInterval(33);
@@ -12,6 +13,12 @@ AnimTimer *AnimTimer::instance() {
     return &s;
 }
 
+void AnimTimer::shutdown() {
+    instance()->m_timer.stop();
+    instance()->m_icons.clear();
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "AnimTimer: shutdown");
+}
+
 void AnimTimer::registerIcon(const QString &key, LottieIcon *icon) {
     m_icons.insert(key, icon);
 }

tools/chatgui/src/animtimer.h

@@ -17,6 +17,7 @@ public:
 
     void activate();
     void deactivate();
+    static void shutdown();
 
 signals:
     void ticked();

tools/chatgui/src/main.cpp

@@ -45,8 +45,9 @@ static struct ShutdownSentinel {
         DWORD threads = count_threads();
         DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "main: threads at exit=%lu", (unsigned long)threads);
         if (threads > 4) {
-            DEBUG_WARN(DEBUG_CATEGORY_DEBUG, "main: %lu hanging threads, ExitProcess", (unsigned long)threads);
-            ExitProcess(0);
+            DEBUG_WARN(DEBUG_CATEGORY_DEBUG, "main: %lu hanging threads, TerminateProcess", (unsigned long)threads);
+            fflush(nullptr);
+            TerminateProcess(GetCurrentProcess(), 0);
         }
 #endif
     }

tools/chatgui/src/mainwindow.cpp

@@ -8,6 +8,7 @@
 #include "creategroupdialog.h"
 #include "invite_link.h"
 #include "sound_manager.h"
+#include "animtimer.h"
 #include "../db/db_manager.h"
 #include "../transport/utun_node.h"
 #include "../transport/gui_bridge.h"
@@ -90,6 +91,7 @@ MainWindow::~MainWindow() {
     DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow — stopping utun node");
     if (m_node) { m_node->stop(); delete m_node; m_node = nullptr; }
     DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow — node stop+delete done");
+    AnimTimer::shutdown();
     MessageList::cleanupAnimations();
     DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow — animations cleaned");
     DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow done");