Sentinel alert WAV files go here (copied from the Mac project).
Expected filenames the Windows native channel looks for:
  chime_clean.wav        (Tier 1)
  warning_medium.wav     (Tier 2)
  siren_critical.wav     (Tier 3)
  voice_clean_1..5.wav
  voice_medium_1..5.wav
  voice_critical_1..5.wav
  voice_fixed_1..5.wav
