Add turn configuration support for assistants

- Introduce a new `turnConfig` field in `AssistantConfig` and `Assistant` models to manage user interaction settings.
- Implement `TurnConfig`, `BargeInConfig`, `VadConfig`, and `TurnDetectionConfig` schemas to define turn management strategies.
- Update the backend to handle turn configuration in the database and during assistant operations.
- Enhance frontend components with a `TurnConfigEditor` for configuring turn settings, including VAD and barge-in strategies.
- Modify existing pages to integrate turn configuration, improving user experience and interaction capabilities.

backend/services/config_resolver.py

@@ -135,6 +135,7 @@ async def resolve_runtime_config(
         prompt=assistant.prompt or "你是一个有帮助的助手。",
         runtimeMode=assistant.runtime_mode,  # type: ignore[arg-type]
         enableInterrupt=assistant.enable_interrupt,
+        turnConfig=assistant.turn_config or {},
         tools=await _tools_for(session, assistant),
         # workflow 图:仅 workflow 类型非空,引擎据此启用图驱动对话
         graph=(assistant.graph or {}) if assistant.type == "workflow" else {},