Fix Docker build errors: remove invalid celery-beat package and update erniebot version

Co-authored-by: yanyuhualb <113324365+yanyuhualb@users.noreply.github.com>

backend/requirements.txt

@@ -18,7 +18,6 @@ hiredis==2.2.3
 
 # Celery任务队列
 celery==5.3.4
-celery-beat==2.5.0
 
 # 认证与安全
 python-jose[cryptography]==3.3.0
@@ -30,7 +29,7 @@ cryptography==41.0.7
 openai==1.3.7
 anthropic==0.7.7
 dashscope==1.14.1  # 阿里通义千问
-erniebot==0.2.5    # 百度文心一言
+erniebot==0.2.1    # 百度文心一言
 
 # 工具库
 httpx==0.25.2