chatgui: report radio output progress with device timing

tools/chatgui/src/sound_manager.cpp

@@ -163,7 +163,7 @@ unsigned SoundManager::renderOutput(ma_engine* engine, const std::array<VoiceAud
         if (engine && ma_engine_read_pcm_frames(engine, destination, count, nullptr) != MA_SUCCESS) {
             ++errors; std::fill_n(destination, count * 2, 0.0f);
         }
-        for (auto* voice : voices) if (voice) voice->mix(destination, count);
+        for (auto* voice : voices) if (voice) voice->mix(destination, count, firstTimeUs + (int64_t)offset * 1000000 / 48000);
         for (unsigned i = 0; i < count * 2; ++i) {
             float value = destination[i];
             destination[i] = std::isfinite(value) ? std::clamp(value, -1.0f, 1.0f) : 0.0f;