feat(voice-client): PySide6 desktop client and Windows build scripts

Add voice_confirmation_client (poll, TTS MP3 playback, mic WAV resolve),
PyInstaller spec, start/build helpers, and API unit tests.

Pending manual testing: end-to-end on OR workstations and packaged exe.

Made-with: Cursor

start_voice_confirmation_client.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# 启动手术室耗材语音确认桌面客户端（PySide6）。
+# 依赖：本机已安装 uv，并已执行过 uv sync --group voice-client
+# 用法：./start_voice_confirmation_client.sh
+
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+cd "$ROOT"
+
+exec uv run --group voice-client python -m voice_confirmation_client "$@"