## Why
Linux voice needs system ALSA plugins and enough buffering to accommodate PipeWire graph cycles without losing capture samples. Voice startup failures also need actionable diagnostics without exposing native error details.
## What changed
- Build and bundle GNU voice helpers and runtimes with primary Linux musl release archives, and sign the archives. Keep Python wheels free of these libraries to preserve `manylinux_2_17` compatibility.
- Discover ALSA plugins in fixed system directories and increase Linux capture and playback buffering to support larger PipeWire graph cycles.
- Report voice failures by stage, preserve negotiation timeout classification, and discard native error sources. Suppress the misleading `requested` closure message after failure cleanup.
- Add explicit Windows MSVC, pkgconf, and CMake toolchain configuration and preserve host architecture in native build environments.
## Testing
Add coverage for Linux release assembly, ALSA plugin discovery, PipeWire capture and playback, classified startup failures, failure cleanup rendering, and Windows build environment handling.
GitOrigin-RevId: d805eace96a669ce3a4489f12e2db6f68f9f7f53
## What changed
- Add `RealtimeWebrtcSession` and cloneable handles for startup, answer negotiation, audio controls, level meters, and error reporting.
- Open devices after answer negotiation and apply the latest controls before enabling audio. Preserve subsequent control transitions in order and close the session if the command queue fills.
- Cancel pending work on explicit close, external cancellation, or final handle drop, with a shared runtime keeping helper reaping alive.
- Add audio-state polling to consume microphone and speaker peaks and detect helper, device, or connection failures.
- Check packaged helper/runtime availability and initialize build information in the standalone TUI for the helper handshake.
## Testing
Add unit and helper-process integration tests covering startup control ordering, queue overflow, cancellation, helper reaping and loss, package availability, SDP debug redaction, and peak accumulation, clamping, and consumption.
GitOrigin-RevId: 458cd80353697f7411cee785f380d1d53aef8416
Benjamin Carlsson