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/__tests__/api/providers.test.ts

@@ -9,6 +9,7 @@ const mockProviders = [
     name: 'OpenAI',
     api_key: 'sk-xxx',
     base_url: 'https://api.openai.com',
+    protocol: 'openai',
     enabled: true,
     created_at: '2025-01-01T00:00:00Z',
     updated_at: '2025-01-01T00:00:00Z',
@@ -18,6 +19,7 @@ const mockProviders = [
     name: 'Anthropic',
     api_key: 'sk-yyy',
     base_url: 'https://api.anthropic.com',
+    protocol: 'anthropic',
     enabled: false,
     created_at: '2025-01-02T00:00:00Z',
     updated_at: '2025-01-02T00:00:00Z',
@@ -34,7 +36,7 @@ describe('providers API', () => {
   describe('listProviders', () => {
     it('returns array of Provider objects with camelCase keys', async () => {
       server.use(
-        http.get('/api/providers', () => {
+        http.get('http://localhost:3000/api/providers', () => {
           return HttpResponse.json(mockProviders);
         }),
       );
@@ -47,6 +49,7 @@ describe('providers API', () => {
           name: 'OpenAI',
           apiKey: 'sk-xxx',
           baseUrl: 'https://api.openai.com',
+          protocol: 'openai',
           enabled: true,
           createdAt: '2025-01-01T00:00:00Z',
           updatedAt: '2025-01-01T00:00:00Z',
@@ -56,6 +59,7 @@ describe('providers API', () => {
           name: 'Anthropic',
           apiKey: 'sk-yyy',
           baseUrl: 'https://api.anthropic.com',
+          protocol: 'anthropic',
           enabled: false,
           createdAt: '2025-01-02T00:00:00Z',
           updatedAt: '2025-01-02T00:00:00Z',
@@ -70,7 +74,7 @@ describe('providers API', () => {
       let receivedBody: Record<string, unknown> | null = null;
 
       server.use(
-        http.post('/api/providers', async ({ request }) => {
+        http.post('http://localhost:3000/api/providers', async ({ request }) => {
           receivedMethod = request.method;
           receivedBody = (await request.json()) as Record<string, unknown>;
           return HttpResponse.json(mockProviders[0]);
@@ -100,6 +104,7 @@ describe('providers API', () => {
         name: 'OpenAI',
         apiKey: 'sk-xxx',
         baseUrl: 'https://api.openai.com',
+        protocol: 'openai',
         enabled: true,
         createdAt: '2025-01-01T00:00:00Z',
         updatedAt: '2025-01-01T00:00:00Z',
@@ -114,7 +119,7 @@ describe('providers API', () => {
       let receivedBody: Record<string, unknown> | null = null;
 
       server.use(
-        http.put('/api/providers/:id', async ({ request, params }) => {
+        http.put('http://localhost:3000/api/providers/:id', async ({ request, params }) => {
           receivedMethod = request.method;
           receivedUrl = new URL(request.url).pathname;
           receivedBody = (await request.json()) as Record<string, unknown>;
@@ -148,7 +153,7 @@ describe('providers API', () => {
       let receivedUrl: string | null = null;
 
       server.use(
-        http.delete('/api/providers/:id', ({ request, params }) => {
+        http.delete('http://localhost:3000/api/providers/:id', ({ request, params }) => {
           receivedMethod = request.method;
           receivedUrl = new URL(request.url).pathname;
           return new HttpResponse(null, { status: 204 });