chatgui: fix sound_manager use-after-free crash on Windows

- Keep mp3Data + ma_decoder alive for sound lifetime (was freed before audio thread)
- Remove MA_SOUND_FLAG_DECODE — stream from decoder instead of pre-decoding
- Shutdown in reverse order: sound → decoder → mp3Data

tools/chatgui/src/sound_manager.cpp

@@ -35,6 +35,10 @@ void SoundManager::shutdown() {
             ma_sound_uninit(it->sound);
             delete it->sound;
         }
+        if (it->decoder) {
+            ma_decoder_uninit(it->decoder);
+            delete it->decoder;
+        }
     }
     m_sounds.clear();
 
@@ -81,33 +85,36 @@ bool SoundManager::loadSound(const QString& name, const QString& qrcPath) {
         qWarning("SoundManager: cannot open %s", qPrintable(qrcPath));
         return false;
     }
-    QByteArray mp3Data = f.readAll();
+
+    LoadedSound ls;
+    ls.mp3Data = f.readAll();
     f.close();
 
+    ls.decoder = new ma_decoder;
     ma_decoder_config decConfig = ma_decoder_config_init_default();
-    ma_decoder decoder;
-    ma_result result = ma_decoder_init_memory(mp3Data.constData(), mp3Data.size(), &decConfig, &decoder);
+    ma_result result = ma_decoder_init_memory(ls.mp3Data.constData(), ls.mp3Data.size(),
+                                               &decConfig, ls.decoder);
     if (result != MA_SUCCESS) {
         qWarning("SoundManager: ma_decoder_init_memory failed for %s (%d)", qPrintable(name), result);
+        delete ls.decoder;
         return false;
     }
 
-    LoadedSound ls;
     ls.sound = new ma_sound;
-    result = ma_sound_init_from_data_source(m_engine, (ma_data_source*)&decoder.ds,
-                                             MA_SOUND_FLAG_DECODE,
-                                             NULL, ls.sound);
-    ma_decoder_uninit(&decoder);
-
+    result = ma_sound_init_from_data_source(m_engine, (ma_data_source*)&ls.decoder->ds,
+                                             0, NULL, ls.sound);
     if (result != MA_SUCCESS) {
         qWarning("SoundManager: sound init failed for %s (%d)", qPrintable(name), result);
+        ma_decoder_uninit(ls.decoder);
+        delete ls.decoder;
         delete ls.sound;
         return false;
     }
 
+    ma_sound_set_volume(ls.sound, m_volume);
     m_sounds.insert(name, ls);
     qDebug("SoundManager: loaded '%s' from %s (%lld bytes)",
-           qPrintable(name), qPrintable(qrcPath), (long long)mp3Data.size());
+           qPrintable(name), qPrintable(qrcPath), (long long)ls.mp3Data.size());
     return true;
 }