feat: 前端适配后端新接口

适配后端统一模型 ID、协议字段、UUID 自动生成和结构化错误响应：

- 类型定义：Provider 新增 protocol 字段，Model 新增 unifiedId，CreateModelInput 移除 id
- API 客户端：提取结构化错误响应中的错误码
- 供应商管理：添加协议选择下拉框和表格列
- 模型管理：移除 ID 输入，显示统一模型 ID（只读）
- Hooks：错误码映射为友好中文消息
- 测试：所有组件测试通过，mock 数据适配新字段
- 文档：更新 README 说明协议字段和统一模型 ID

frontend/src/pages/Providers/ModelForm.tsx

@@ -4,7 +4,6 @@ import type { Provider, Model } from '@/types';
 import type { SubmitContext } from 'tdesign-react/es/form/type';
 
 interface ModelFormValues {
-  id: string;
   providerId: string;
   modelName: string;
   enabled: boolean;
@@ -38,7 +37,6 @@ export function ModelForm({
       if (model) {
         // 编辑模式：设置现有值
         form.setFieldsValue({
-          id: model.id,
           providerId: model.providerId,
           modelName: model.modelName,
           enabled: model.enabled,
@@ -73,9 +71,14 @@ export function ModelForm({
       destroyOnClose
     >
       <Form form={form} layout="vertical" onSubmit={handleSubmit}>
-        <Form.FormItem label="ID" name="id" rules={[{ required: true, message: '请输入模型 ID' }]}>
-          <Input disabled={isEdit} placeholder="例如: gpt-4o" />
-        </Form.FormItem>
+        {isEdit && model?.unifiedId && (
+          <Form.FormItem label="统一模型 ID">
+            <Input value={model.unifiedId} disabled />
+            <div style={{ color: '#999', fontSize: 12, marginTop: 4 }}>
+              格式：provider_id/model_name
+            </div>
+          </Form.FormItem>
+        )}
 
         <Form.FormItem
           label="供应商"

frontend/src/pages/Providers/ModelTable.tsx

@@ -14,6 +14,13 @@ export function ModelTable({ providerId, onAdd, onEdit }: ModelTableProps) {
   const deleteModel = useDeleteModel();
 
   const columns: PrimaryTableCol<Model>[] = [
+    {
+      title: '统一模型 ID',
+      colKey: 'unifiedId',
+      width: 250,
+      ellipsis: true,
+      cell: ({ row }) => row.unifiedId || `${row.providerId}/${row.modelName}`,
+    },
     {
       title: '模型名称',
       colKey: 'modelName',

frontend/src/pages/Providers/ProviderForm.tsx

@@ -1,5 +1,5 @@
 import { useEffect } from 'react';
-import { Dialog, Form, Input, Switch } from 'tdesign-react';
+import { Dialog, Form, Input, Switch, Select } from 'tdesign-react';
 import type { Provider } from '@/types';
 import type { SubmitContext } from 'tdesign-react/es/form/type';
 
@@ -8,6 +8,7 @@ interface ProviderFormValues {
   name: string;
   apiKey: string;
   baseUrl: string;
+  protocol: 'openai' | 'anthropic';
   enabled: boolean;
 }
 
@@ -39,12 +40,13 @@ export function ProviderForm({
           name: provider.name,
           apiKey: '',
           baseUrl: provider.baseUrl,
+          protocol: provider.protocol,
           enabled: provider.enabled,
         });
       } else {
         // 新增模式：重置表单
         form.reset();
-        form.setFieldsValue({ enabled: true });
+        form.setFieldsValue({ enabled: true, protocol: 'openai' });
       }
     }
   }, [open, provider]); // 移除form依赖，避免循环
@@ -95,6 +97,13 @@ export function ProviderForm({
           <Input placeholder="例如: https://api.openai.com/v1" />
         </Form.FormItem>
 
+        <Form.FormItem label="协议" name="protocol" rules={[{ required: true, message: '请选择协议' }]}>
+          <Select>
+            <Select.Option value="openai">OpenAI</Select.Option>
+            <Select.Option value="anthropic">Anthropic</Select.Option>
+          </Select>
+        </Form.FormItem>
+
         <Form.FormItem label="启用" name="enabled">
           <Switch />
         </Form.FormItem>

frontend/src/pages/Providers/ProviderTable.tsx

@@ -40,6 +40,16 @@ export function ProviderTable({
       colKey: 'baseUrl',
       ellipsis: true,
     },
+    {
+      title: '协议',
+      colKey: 'protocol',
+      width: 100,
+      cell: ({ row }) => (
+        <Tag theme={row.protocol === 'openai' ? 'primary' : 'success'}>
+          {row.protocol === 'openai' ? 'OpenAI' : 'Anthropic'}
+        </Tag>
+      ),
+    },
     {
       title: 'API Key',
       colKey: 'apiKey',