feat: 站点 JSON、语音终端 WebSocket 指派与客户端联调

- 用 OR_SITE_CONFIG_JSON_FILE 统一术间配置（video_rtsp_urls + voice_or_room_bindings）
- VoiceTerminalHub：assignment、WS 推送与 HTTP 查询；开录/停录后 notify
- 一键联调 orchestrate-and-start 与 /client/surgeries/start 共用指派逻辑，修复 demo 路径不发 WS
- 语音桌面端：SIGINT 退出、shutdown 清理、仅 WS 指派、固定 pending 轮询间隔、界面仅保留录音时长
- 新增/调整契约与绑定测试，文档与示例配置同步

Made-with: Cursor

app/services/video/backend_resolver.py

@@ -54,7 +54,7 @@ class BackendResolver:
         return VideoBackendKind.RTSP
 
     def rtsp_url_for_camera(self, camera_id: str) -> str:
-        # Re-read on each use so VIDEO_RTSP_URLS_JSON_FILE can be hot-updated (e.g. dev orchestrator).
+        # Re-read on each use so OR_SITE_CONFIG_JSON_FILE can be hot-updated (e.g. dev orchestrator).
         m = self._s.video_rtsp_url_map()
         if camera_id in m:
             return m[camera_id]
@@ -67,8 +67,8 @@ class BackendResolver:
                     f"video_rtsp_url_template missing placeholder: {exc}"
                 ) from exc
         raise ValueError(
-            f"No RTSP URL for camera_id={camera_id!r}: set VIDEO_RTSP_URLS_JSON_FILE, "
-            f"VIDEO_RTSP_URLS_JSON, or VIDEO_RTSP_URL_TEMPLATE"
+            f"No RTSP URL for camera_id={camera_id!r}: set OR_SITE_CONFIG_JSON_FILE "
+            f"(video_rtsp_urls) or VIDEO_RTSP_URL_TEMPLATE"
         )
 
     def rtsp_url_after_hikvision_login(self, camera_id: str) -> str: