The probe drove PipeWire directly and stubbed out everywhere else, so the
Windows port had no way to isolate the local output path. win_probe mirrors
unix_probe against CpalBackend: same phase-continuous sine, same fill-paced
production against PLAYBACK_TARGET_SAMPLES, same playout-health log tailer.
NOT COMPILE-VERIFIED. The new module is behind #[cfg(windows)], so a Linux
host never type-checks it; it needs a cargo check on a Windows target (or the
mingw cross target) before it is trusted.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>