## Summary
- Spawn system audio players (`ffplay` / `afplay` / `aplay`) with `hermes_subprocess_env(inherit_credentials=False)`.
- Prevent gateway tokens and provider API keys from leaking into OS media helpers.
- Add a regression test asserting scrubbed env on `Popen`.
## Salvage / credit
Sibling of #70342 / incomplete #56332 (TTS/STT command scrub) on the voice-mode playback path.