feat: AI聊天室多Agent协作讨论平台

- 实现Agent管理，支持AI辅助生成系统提示词
- 支持多个AI提供商（OpenRouter、智谱、MiniMax等）
- 实现聊天室和讨论引擎
- WebSocket实时消息推送
- 前端使用React + Ant Design
- 后端使用FastAPI + MongoDB

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/utils/proxy_handler.py

@@ -0,0 +1,135 @@
+"""
+代理处理模块
+处理HTTP代理配置
+"""
+from typing import Optional, Dict, Any
+import httpx
+from loguru import logger
+
+from config import settings
+
+
+def get_proxy_dict(
+    use_proxy: bool,
+    proxy_config: Optional[Dict[str, Any]] = None
+) -> Optional[Dict[str, str]]:
+    """
+    获取代理配置字典
+    
+    Args:
+        use_proxy: 是否使用代理
+        proxy_config: 代理配置
+        
+    Returns:
+        代理配置字典或None
+    """
+    if not use_proxy:
+        return None
+    
+    proxies = {}
+    
+    if proxy_config:
+        http_proxy = proxy_config.get("http_proxy")
+        https_proxy = proxy_config.get("https_proxy")
+    else:
+        # 使用全局默认代理
+        http_proxy = settings.DEFAULT_HTTP_PROXY
+        https_proxy = settings.DEFAULT_HTTPS_PROXY
+    
+    if http_proxy:
+        proxies["http://"] = http_proxy
+    if https_proxy:
+        proxies["https://"] = https_proxy
+    
+    return proxies if proxies else None
+
+
+def get_http_client(
+    use_proxy: bool = False,
+    proxy_config: Optional[Dict[str, Any]] = None,
+    timeout: int = 60,
+    **kwargs
+) -> httpx.AsyncClient:
+    """
+    获取配置好的HTTP异步客户端
+    
+    Args:
+        use_proxy: 是否使用代理
+        proxy_config: 代理配置
+        timeout: 超时时间(秒)
+        **kwargs: 其他httpx参数
+        
+    Returns:
+        配置好的httpx.AsyncClient实例
+    """
+    proxies = get_proxy_dict(use_proxy, proxy_config)
+    
+    client_kwargs = {
+        "timeout": httpx.Timeout(timeout),
+        "follow_redirects": True,
+        **kwargs
+    }
+    
+    if proxies:
+        client_kwargs["proxies"] = proxies
+        logger.debug(f"HTTP客户端使用代理: {proxies}")
+    
+    return httpx.AsyncClient(**client_kwargs)
+
+
+async def test_proxy_connection(
+    proxy_config: Dict[str, Any],
+    test_url: str = "https://www.google.com"
+) -> Dict[str, Any]:
+    """
+    测试代理连接是否可用
+    
+    Args:
+        proxy_config: 代理配置
+        test_url: 测试URL
+        
+    Returns:
+        测试结果字典，包含 success, message, latency_ms
+    """
+    try:
+        async with get_http_client(
+            use_proxy=True,
+            proxy_config=proxy_config,
+            timeout=10
+        ) as client:
+            import time
+            start = time.time()
+            response = await client.get(test_url)
+            latency = (time.time() - start) * 1000
+            
+            if response.status_code == 200:
+                return {
+                    "success": True,
+                    "message": "代理连接正常",
+                    "latency_ms": round(latency, 2)
+                }
+            else:
+                return {
+                    "success": False,
+                    "message": f"代理返回状态码: {response.status_code}",
+                    "latency_ms": round(latency, 2)
+                }
+                
+    except httpx.ProxyError as e:
+        return {
+            "success": False,
+            "message": f"代理连接失败: {str(e)}",
+            "latency_ms": None
+        }
+    except httpx.TimeoutException:
+        return {
+            "success": False,
+            "message": "代理连接超时",
+            "latency_ms": None
+        }
+    except Exception as e:
+        return {
+            "success": False,
+            "message": f"连接错误: {str(e)}",
+            "latency_ms": None
+        }