feat: add HTTP/SOCKS5 proxy support for API endpoints

- Add proxy field to ProviderEndpoint database model with migration
- Add ProxyConfig Pydantic model for proxy URL validation
- Extend HTTP client pool with create_client_with_proxy method
- Integrate proxy configuration in chat_handler_base.py and cli_handler_base.py
- Update admin API endpoints to support proxy configuration CRUD
- Add proxy configuration UI in frontend EndpointFormDialog

Fixes #28

src/api/admin/endpoints/routes.py

@@ -202,6 +202,7 @@ class AdminCreateProviderEndpointAdapter(AdminApiAdapter):
             rate_limit=self.endpoint_data.rate_limit,
             is_active=True,
             config=self.endpoint_data.config,
+            proxy=self.endpoint_data.proxy.model_dump() if self.endpoint_data.proxy else None,
             created_at=now,
             updated_at=now,
         )
@@ -284,6 +285,9 @@ class AdminUpdateProviderEndpointAdapter(AdminApiAdapter):
             raise NotFoundException(f"Endpoint {self.endpoint_id} 不存在")
 
         update_data = self.endpoint_data.model_dump(exclude_unset=True)
+        # 把 proxy 转换为 dict 存储
+        if "proxy" in update_data and update_data["proxy"] is not None:
+            update_data["proxy"] = dict(update_data["proxy"])
         for field, value in update_data.items():
             setattr(endpoint, field, value)
         endpoint.updated_at = datetime.now(timezone.utc)

src/api/handlers/base/chat_handler_base.py

@@ -466,7 +466,13 @@ class ChatHandlerBase(BaseMessageHandler, ABC):
             pool=config.http_pool_timeout,
         )
 
-        http_client = httpx.AsyncClient(timeout=timeout_config, follow_redirects=True)
+        # 创建 HTTP 客户端（支持代理配置）
+        from src.clients.http_client import HTTPClientPool
+
+        http_client = HTTPClientPool.create_client_with_proxy(
+            proxy_config=endpoint.proxy,
+            timeout=timeout_config,
+        )
         try:
             response_ctx = http_client.stream(
                 "POST", url, json=provider_payload, headers=provider_headers
@@ -634,10 +640,14 @@ class ChatHandlerBase(BaseMessageHandler, ABC):
             logger.info(f"  [{self.request_id}] 发送非流式请求: Provider={provider.name}, "
                 f"模型={model} -> {mapped_model or '无映射'}")
 
-            async with httpx.AsyncClient(
-                timeout=float(endpoint.timeout),
-                follow_redirects=True,
-            ) as http_client:
+            # 创建 HTTP 客户端（支持代理配置）
+            from src.clients.http_client import HTTPClientPool
+
+            http_client = HTTPClientPool.create_client_with_proxy(
+                proxy_config=endpoint.proxy,
+                timeout=httpx.Timeout(float(endpoint.timeout)),
+            )
+            async with http_client:
                 resp = await http_client.post(url, json=provider_payload, headers=provider_hdrs)
 
                 status_code = resp.status_code

src/api/handlers/base/cli_handler_base.py

@@ -454,7 +454,13 @@ class CliMessageHandlerBase(BaseMessageHandler):
             f"Key=***{key.api_key[-4:]}, "
             f"原始模型={ctx.model}, 映射后={mapped_model or '无映射'}, URL模型={url_model}")
 
-        http_client = httpx.AsyncClient(timeout=timeout_config, follow_redirects=True)
+        # 创建 HTTP 客户端（支持代理配置）
+        from src.clients.http_client import HTTPClientPool
+
+        http_client = HTTPClientPool.create_client_with_proxy(
+            proxy_config=endpoint.proxy,
+            timeout=timeout_config,
+        )
         try:
             response_ctx = http_client.stream(
                 "POST", url, json=provider_payload, headers=provider_headers
@@ -1419,10 +1425,14 @@ class CliMessageHandlerBase(BaseMessageHandler):
                 f"Key=***{key.api_key[-4:]}, "
                 f"原始模型={model}, 映射后={mapped_model or '无映射'}, URL模型={url_model}")
 
-            async with httpx.AsyncClient(
-                timeout=float(endpoint.timeout),
-                follow_redirects=True,
-            ) as http_client:
+            # 创建 HTTP 客户端（支持代理配置）
+            from src.clients.http_client import HTTPClientPool
+
+            http_client = HTTPClientPool.create_client_with_proxy(
+                proxy_config=endpoint.proxy,
+                timeout=httpx.Timeout(float(endpoint.timeout)),
+            )
+            async with http_client:
                 resp = await http_client.post(url, json=provider_payload, headers=provider_headers)
 
                 status_code = resp.status_code