audio_win.ll implements audio.ll's snd_* contract over XAudio2 from IR: a
source voice per clip, restart on play, LoopCount for loops, SetVolume,
SetFrequencyRatio and a balance pan through SetOutputMatrix, with the COM
slots taken from the SDK's xaudio2.h. Clips are RIFF WAVE read through
lp_pak_open (weakly referenced), so a packed sound loads directly. ludicc links
it with xaudio2 and ole32, and silences xinput.lib's importeddllmain warning.
Verified: ludic-dev test 135/135, selfhost-test 32/32; on the PC a harness
loads, plays, pans, loops and stops clips, and Maroon Lake windowed reports
"sound: 31 of 31 clips loaded".
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>