fix: true pause/resume with position preservation

- SoundManager: pauseCurrentPcm()/resumeCurrentPcm() — stop/start without destroy
- VoicePlayState: added paused/pausedPosSec fields
- editorEvent: 3-state logic — playing→pause, paused→resume, stopped→new
- Different file click: stops old with full cleanup, plays new from start
- Timer: skips paused items, full cleanup on auto-complete

tools/chatgui/src/sound_manager.cpp

@@ -172,6 +172,14 @@ void SoundManager::playRawPcm(const int16_t* pcm, int sampleCount, int sampleRat
     ma_sound_start(m_currentPcmSound);
 }
 
+void SoundManager::pauseCurrentPcm() {
+    if (m_currentPcmSound) ma_sound_stop(m_currentPcmSound);
+}
+
+void SoundManager::resumeCurrentPcm() {
+    if (m_currentPcmSound) ma_sound_start(m_currentPcmSound);
+}
+
 void SoundManager::stopCurrentPcm() {
     if (m_currentPcmSound) {
         ma_sound_stop(m_currentPcmSound);