chatgui: fix rlottie thread hang on Windows shutdown

Root cause: librlottie RleTaskScheduler creates 32 worker threads on first
lottie_animation_from_data call. These pthreads wait in WaitForMultipleObjects(INFINITE)
and never exit. On MinGW, exit()/pthread_join blocks forever.

Changes:
- messagelist: s_icons moved to file-static; cleanupAnimations() clears them,
  calling lottie_animation_destroy BEFORE static destruction
- mainwindow: ~MainWindow calls MessageList::cleanupAnimations() after node stop
- main: ShutdownSentinel counts threads at exit; if >4 remaining, calls
  ExitProcess(0) to bypass CRT pthread_join hang
- main: if rlottie properly shuts down (<=4 threads), normal return (no ExitProcess)

tools/chatgui/src/main.cpp

@@ -5,6 +5,7 @@
 #include <cstdio>
 #ifdef _WIN32
 #include <windows.h>
+#include <tlhelp32.h>
 #endif
 #include "mainwindow.h"
 #include "../db/db_manager.h"
@@ -15,6 +16,19 @@
 #ifdef _WIN32
 static UtunNode* g_ctrl_node = nullptr;
 
+static DWORD count_threads(void) {
+    DWORD pid = GetCurrentProcessId(), count = 0;
+    HANDLE snap = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
+    if (snap == INVALID_HANDLE_VALUE) return 0;
+    THREADENTRY32 te = { sizeof(te) };
+    if (Thread32First(snap, &te)) {
+        do { if (te.th32OwnerProcessID == pid) count++; }
+        while (Thread32Next(snap, &te));
+    }
+    CloseHandle(snap);
+    return count;
+}
+
 static BOOL WINAPI console_ctrl_handler(DWORD dwCtrlType) {
     if (dwCtrlType == CTRL_C_EVENT || dwCtrlType == CTRL_BREAK_EVENT) {
         if (g_ctrl_node) g_ctrl_node->requestStop();
@@ -27,6 +41,14 @@ static BOOL WINAPI console_ctrl_handler(DWORD dwCtrlType) {
 static struct ShutdownSentinel {
     ~ShutdownSentinel() {
         DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "main: static destructors done");
+#ifdef _WIN32
+        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);
+        }
+#endif
     }
 } g_shutdown_sentinel;
 

tools/chatgui/src/mainwindow.cpp

@@ -90,6 +90,8 @@ 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");
+    MessageList::cleanupAnimations();
+    DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow — animations cleaned");
     DEBUG_DEBUG(DEBUG_CATEGORY_DEBUG, "MainWindow: ~MainWindow done");
 }
 

tools/chatgui/src/messagelist.cpp

@@ -7,6 +7,7 @@
 #include "animtimer.h"
 #include "lottieicon.h"
 #include "../db/db_manager.h"
+#include "../../lib/debug_config.h"
 #include <QVBoxLayout>
 #include <QPainter>
 #include <QPixmap>
@@ -18,6 +19,8 @@
 #include <vector>
 #include <memory>
 
+static std::vector<std::unique_ptr<LottieIcon>> s_icons;
+
 extern "C" {
 #include "../transport/gui_bridge.h"
 #include "../transport/chat_core.h"
@@ -95,7 +98,6 @@ MessageList::MessageList(DbManager* db, QWidget *parent)
     m_view->setBackgroundImage("../resources/bg.jpg");
     layout->addWidget(m_view, 1);
 
-    static std::vector<std::unique_ptr<LottieIcon>> s_icons;
     if (s_icons.empty()) {
         for (const auto &cat : builtinEmojiSet()) {
             for (const auto &e : cat.items) {
@@ -412,3 +414,10 @@ void MessageList::updateReadPosition() {
         chat_core_save_ui_state(posKey.constData(), posVal.constData());
     }
 }
+
+void MessageList::cleanupAnimations() {
+    size_t n = s_icons.size();
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "MessageList: cleanupAnimations clearing %zu icons", n);
+    s_icons.clear();
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "MessageList: cleanupAnimations done");
+}

tools/chatgui/src/messagelist.h

@@ -19,6 +19,7 @@ public:
     void loadChannel(const QString& channelId);
     void refresh();
     void saveChannelState();
+    static void cleanupAnimations();
     void addMessage(const QString& channelId, quint64 authorNodeId,
                     const QByteArray& content, qint64 timestamp);