Replace PulseAudio with PipeWire/WirePlumber audio stack in WSLg

[linghengqian]

• Fixes use Pipewire instead of PA #290 .
• Replace PulseAudio with PipeWire/WirePlumber audio stack in WSLg.

[linghengqian]

@microsoft-github-policy-service agree

[benhillis]

Triage note (2026-05): Thanks for the substantial work — replacing PulseAudio with PipeWire/WirePlumber is squarely on the roadmap (tracked in #290, with 40+ reactions) and we want to land this. A few things will hold the merge button:

1. We need to validate audio behavior end-to-end against current RDP audio playback and capture paths. The pipewire-wslg-rdp.patch and pipewire-rdp-module.c carry the equivalent of the existing PulseAudio RDP module — verifying parity (sample rates, latency, capture devices, mute/volume integration with Windows) is the bulk of the review.
2. cgmanifest.json will need entries for PipeWire / WirePlumber so Component Governance is happy.
3. An internal buddy build through the full Azure Pipelines flow before merge.

Not asking for changes yet — just setting expectations. If you want to chip away at (1) and (2) preemptively that would help.

[linghengqian]

I'm glad Microsoft is willing to take on this work, especially since I don't actually have an Azure account to test the corresponding CI files. Should I close this PR?