fix(frontend): 修复合并审阅发现的构建与契约问题

恢复 Vue TypeScript 生产构建，补齐可运行页面壳子，并修复文件树与 SSE 状态问题。

按 FastAPI Wire Contract 统一 Service DTO 映射，同时补充前端开发说明和问题修复复盘。

frontend/src/services/providerService.ts

@@ -1,36 +1,67 @@
 import apiClient from './apiClient'
-import type { ProviderConfig, ModelInfo } from '@/contracts'
+import type { ApiModelInfo, ApiProviderConfig, ModelCapability, ModelInfo, OperationResponse, ProviderConfig } from '@/contracts'
 
-export async function listProviders(): Promise<ProviderConfig[]> {
-  try {
-    return await apiClient.get('/api/providers')
-  } catch {
-    return mockProviders
+function capabilityMap(capabilities: string[]): Partial<ModelCapability> {
+  return Object.fromEntries(capabilities.map((capability) => [capability, true])) as Partial<ModelCapability>
+}
+
+function toProvider(provider: ApiProviderConfig): ProviderConfig {
+  return {
+    provider_id: provider.provider_id,
+    provider_type: provider.provider_type,
+    name: provider.name,
+    base_url: provider.base_url ?? undefined,
+    default_model: provider.default_model ?? '',
+    enabled: provider.enabled,
+    capabilities: capabilityMap(provider.capabilities),
+    credential_id: provider.credential_id ?? undefined,
+    has_credential: Boolean(provider.credential_id) || provider.provider_type === 'mock',
   }
 }
 
+function toModel(model: ApiModelInfo): ModelInfo {
+  return { model_id: model.model, name: model.display_name, capabilities: capabilityMap(model.capabilities) }
+}
+
+export async function listProviders(): Promise<ProviderConfig[]> {
+  const response = await apiClient.get<{ items: ApiProviderConfig[] }>('/api/providers')
+  return response.items.map(toProvider)
+}
+
 export async function getProvider(providerId: string): Promise<ProviderConfig> {
-  return apiClient.get(`/api/providers/${providerId}`)
+  return toProvider(await apiClient.get<ApiProviderConfig>(`/api/providers/${providerId}`))
 }
 
-export async function createProvider(data: Omit<ProviderConfig, 'provider_id'> & { api_key?: string }): Promise<ProviderConfig> {
-  return apiClient.post('/api/providers', data)
+export async function createProvider(data: Omit<ProviderConfig, 'provider_id'>): Promise<ProviderConfig> {
+  const response = await apiClient.post<ApiProviderConfig>('/api/providers', {
+    provider_type: data.provider_type,
+    name: data.name,
+    base_url: data.base_url,
+    default_model: data.default_model || null,
+    credential_id: data.credential_id,
+    enabled: data.enabled,
+  })
+  return toProvider(response)
 }
 
-export async function updateProvider(providerId: string, data: Partial<ProviderConfig> & { api_key?: string }): Promise<ProviderConfig> {
-  return apiClient.patch(`/api/providers/${providerId}`, data)
+export async function updateProvider(providerId: string, data: Partial<ProviderConfig>): Promise<ProviderConfig> {
+  const response = await apiClient.patch<ApiProviderConfig>(`/api/providers/${providerId}`, {
+    name: data.name,
+    base_url: data.base_url,
+    default_model: data.default_model,
+    credential_id: data.credential_id,
+    enabled: data.enabled,
+  })
+  return toProvider(response)
 }
 
-export async function deleteProvider(providerId: string): Promise<void> {
+export async function deleteProvider(providerId: string): Promise<OperationResponse> {
   return apiClient.delete(`/api/providers/${providerId}`)
 }
 
 export async function listModels(providerId: string): Promise<ModelInfo[]> {
-  try {
-    return await apiClient.get(`/api/providers/${providerId}/models`)
-  } catch {
-    return mockModels[providerId] || []
-  }
+  const response = await apiClient.get<{ provider_id: string; items: ApiModelInfo[] }>(`/api/providers/${providerId}/models`)
+  return response.items.map(toModel)
 }
 
 export interface TestResult {
@@ -42,8 +73,8 @@ export interface TestResult {
 
 export async function testProvider(providerId: string): Promise<TestResult> {
   try {
-    const result = await apiClient.post<{ success: boolean; latency_ms: number }>('/api/providers/test', { provider_id: providerId })
-    return { success: result.success, latency_ms: result.latency_ms }
+    const result = await apiClient.post<{ success: boolean; latency_ms?: number | null; message: string }>('/api/providers/test', { provider_id: providerId })
+    return { success: result.success, latency_ms: result.latency_ms ?? undefined, error_message: result.success ? undefined : result.message }
   } catch (e: any) {
     return { success: false, error_code: e.code || 'TEST_FAILED', error_message: e.message }
   }
@@ -51,7 +82,7 @@ export async function testProvider(providerId: string): Promise<TestResult> {
 
 export const mockProviders: ProviderConfig[] = [
   {
-    provider_id: 'mock-provider',
+    provider_id: 'mock',
     provider_type: 'mock',
     name: 'Mock Provider (测试)',
     default_model: 'mock-1',
@@ -69,7 +100,7 @@ export const mockProviders: ProviderConfig[] = [
   },
   {
     provider_id: 'openai-compat-1',
-    provider_type: 'openai-compatible',
+    provider_type: 'openai_compatible',
     name: 'OpenAI 兼容服务',
     base_url: 'https://api.openai.com/v1',
     default_model: 'gpt-4o-mini',
@@ -106,7 +137,7 @@ export const mockProviders: ProviderConfig[] = [
 ]
 
 export const mockModels: Record<string, ModelInfo[]> = {
-  'mock-provider': [
+  mock: [
     {
       model_id: 'mock-1',
       name: 'Mock Model v1',