重构语音能力配置与逻辑，统一音频输入输出开关并优化语音回复判断

app/api/endpoints/system.py

@@ -494,6 +494,7 @@ async def get_user_global_setting(_: User = Depends(get_current_active_user_asyn
     info = settings.model_dump(
         include={
             "AI_AGENT_ENABLE",
+            "LLM_SUPPORT_AUDIO_INPUT_OUTPUT",
             "RECOGNIZE_SOURCE",
             "SEARCH_SOURCE",
             "AI_RECOMMEND_ENABLED",
@@ -503,6 +504,7 @@ async def get_user_global_setting(_: User = Depends(get_current_active_user_asyn
     # 智能助手总开关未开启，智能推荐状态强制返回False
     if not settings.AI_AGENT_ENABLE:
         info["AI_RECOMMEND_ENABLED"] = False
+        info["LLM_SUPPORT_AUDIO_INPUT_OUTPUT"] = False
 
     # 追加用户唯一ID和订阅分享管理权限
     share_admin = SubscribeHelper().is_admin_user()