Keep native audio on one clock

The user reports a painful sound beginning when a race starts and says the menu mouse issue no longer seems present.

Observed in Session::pass and Audio::advance_to: the window called the headless audio clock and then Audio::pump filled the cpal output queue. advance_to now returns when an output device is open, so native playback advances through the device queue only. Headless sound dumps still use advance_to. The sound core and measured Gold behavior are unchanged.

cargo fmt --all -- --check and cargo test --release -p unpod -p pod-sound --quiet pass. No game assets were extracted in this session.

The existing Gold measurement records the engine input rising to a high steady value at GO. After rebuilding, listen again; if the sound remains painful, lower SoundFxVolume in the options or run with --mute, then capture a short sound dump to identify the source.