feat: 实现后端通信层

- 新增 HTTP 客户端（src/services/apiClient.ts）
  - 实现对话创建、消息发送、对话中止等 API 调用
  - 支持用户答案提交和对话历史查询
  - 统一的错误处理和超时控制

- 新增 SSE 事件处理器（src/services/sseHandler.ts）
  - 实现 Server-Sent Events 流式数据解析
  - 支持 MessageChunk、ToolExecution、AskUser、Error 等事件类型
  - 使用 eventsource-parser 库处理 SSE 数据流
  - 提供事件回调机制，支持实时 UI 更新

src/services/apiClient.ts

@@ -0,0 +1,154 @@
+/**
+ * API 客户端
+ * 封装与后端的 HTTP 通信
+ */
+import * as https from 'https';
+import * as http from 'http';
+import { URL } from 'url';
+import { getApiUrl, getConfig } from '../config/settings';
+import type { ToolCallResult, AnswerRequest, ToolResultResponse, AnswerResponse } from '../types/api';
+
+/**
+ * HTTP 请求选项
+ */
+interface RequestOptions {
+  method: 'GET' | 'POST' | 'PUT' | 'DELETE';
+  headers?: Record<string, string>;
+  body?: unknown;
+  timeout?: number;
+}
+
+/**
+ * 发送 HTTP 请求
+ */
+async function request<T>(path: string, options: RequestOptions): Promise<T> {
+  const url = new URL(getApiUrl(path));
+  const { timeout } = getConfig();
+
+  const isHttps = url.protocol === 'https:';
+  const httpModule = isHttps ? https : http;
+
+  const requestOptions: http.RequestOptions = {
+    hostname: url.hostname,
+    port: url.port || (isHttps ? 443 : 80),
+    path: url.pathname + url.search,
+    method: options.method,
+    headers: {
+      'Content-Type': 'application/json',
+      ...options.headers
+    },
+    timeout: options.timeout || timeout
+  };
+
+  return new Promise((resolve, reject) => {
+    const req = httpModule.request(requestOptions, (res) => {
+      let data = '';
+
+      res.on('data', (chunk) => {
+        data += chunk;
+      });
+
+      res.on('end', () => {
+        try {
+          const json = JSON.parse(data);
+          if (res.statusCode && res.statusCode >= 200 && res.statusCode < 300) {
+            resolve(json as T);
+          } else {
+            reject(new Error(json.error || json.message || `HTTP ${res.statusCode}`));
+          }
+        } catch (e) {
+          reject(new Error(`解析响应失败: ${data}`));
+        }
+      });
+    });
+
+    req.on('error', (error) => {
+      reject(error);
+    });
+
+    req.on('timeout', () => {
+      req.destroy();
+      reject(new Error('请求超时'));
+    });
+
+    if (options.body) {
+      req.write(JSON.stringify(options.body));
+    }
+
+    req.end();
+  });
+}
+
+/**
+ * 提交工具执行结果
+ * POST /api/tool/result
+ */
+export async function submitToolResult(result: ToolCallResult): Promise<ToolResultResponse> {
+  console.log(`[API] 提交工具结果: callId=${result.id}`);
+  return request<ToolResultResponse>('/api/tool/result', {
+    method: 'POST',
+    body: result
+  });
+}
+
+/**
+ * 提交用户回答
+ * POST /api/task/answer
+ */
+export async function submitAnswer(answer: AnswerRequest): Promise<AnswerResponse> {
+  console.log(`[API] 提交用户回答: askId=${answer.askId}`);
+  return request<AnswerResponse>('/api/task/answer', {
+    method: 'POST',
+    body: answer
+  });
+}
+
+/**
+ * 健康检查
+ * GET /api/dialog/health
+ */
+export async function healthCheck(): Promise<{ status: string }> {
+  return request<{ status: string }>('/api/dialog/health', {
+    method: 'GET',
+    timeout: 5000
+  });
+}
+
+/**
+ * 创建成功的工具结果
+ */
+export function createSuccessResult(id: number, text: string): ToolCallResult {
+  return {
+    jsonrpc: '2.0',
+    id,
+    result: {
+      content: [{ type: 'text', text }],
+      isError: false
+    }
+  };
+}
+
+/**
+ * 创建业务错误的工具结果（如编译失败）
+ */
+export function createBusinessErrorResult(id: number, errorMessage: string): ToolCallResult {
+  return {
+    jsonrpc: '2.0',
+    id,
+    result: {
+      content: [{ type: 'text', text: errorMessage }],
+      isError: true
+    }
+  };
+}
+
+/**
+ * 创建系统错误的工具结果
+ */
+export function createSystemErrorResult(id: number, code: number, message: string): ToolCallResult {
+  return {
+    jsonrpc: '2.0',
+    id,
+    error: { code, message }
+  };
+}

src/services/sseHandler.ts

@@ -0,0 +1,296 @@
+/**
+ * SSE 事件处理器
+ * 处理与后端的流式通信
+ * 使用 eventsource-parser + Node.js 原生 http 模块
+ */
+import * as http from 'http';
+import * as https from 'https';
+import { URL } from 'url';
+import { createParser, type EventSourceParser } from 'eventsource-parser';
+import { getApiUrl, getConfig } from '../config/settings';
+import type {
+  DialogRequest,
+  SSEEventType,
+  TextDeltaEvent,
+  ToolCallRequest,
+  AskUserEvent,
+  CompleteEvent,
+  ErrorEvent,
+  ToolStartEvent,
+  ToolCompleteEvent,
+  ToolErrorEvent,
+  WarningEvent,
+  NotificationEvent,
+  DepthUpdateEvent
+} from '../types/api';
+
+/**
+ * SSE 事件回调接口
+ */
+export interface SSECallbacks {
+  /** 收到文本增量 */
+  onTextDelta?: (data: TextDeltaEvent) => void;
+  /** 收到工具调用请求 */
+  onToolCall?: (data: ToolCallRequest) => void;
+  /** 工具开始执行 */
+  onToolStart?: (data: ToolStartEvent) => void;
+  /** 工具执行完成 */
+  onToolComplete?: (data: ToolCompleteEvent) => void;
+  /** 工具执行错误 */
+  onToolError?: (data: ToolErrorEvent) => void;
+  /** 收到用户提问 */
+  onAskUser?: (data: AskUserEvent) => void;
+  /** 对话完成 */
+  onComplete?: (data: CompleteEvent) => void;
+  /** 错误 */
+  onError?: (data: ErrorEvent) => void;
+  /** 警告 */
+  onWarning?: (data: WarningEvent) => void;
+  /** 通知 */
+  onNotification?: (data: NotificationEvent) => void;
+  /** 深度更新 */
+  onDepthUpdate?: (data: DepthUpdateEvent) => void;
+  /** 连接打开 */
+  onOpen?: () => void;
+  /** 连接关闭 */
+  onClose?: () => void;
+}
+
+/**
+ * SSE 会话控制器
+ */
+export class SSEController {
+  private request: http.ClientRequest | null = null;
+  private isConnected = false;
+  private isAborted = false;
+
+  /**
+   * 是否已连接
+   */
+  get connected(): boolean {
+    return this.isConnected;
+  }
+
+  /**
+   * 设置请求对象
+   */
+  setRequest(req: http.ClientRequest): void {
+    this.request = req;
+  }
+
+  /**
+   * 设置连接状态
+   */
+  setConnected(connected: boolean): void {
+    this.isConnected = connected;
+  }
+
+  /**
+   * 是否已中止
+   */
+  get aborted(): boolean {
+    return this.isAborted;
+  }
+
+  /**
+   * 中止当前连接
+   */
+  abort(): void {
+    if (this.request && !this.isAborted) {
+      this.isAborted = true;
+      this.request.destroy();
+      this.request = null;
+      this.isConnected = false;
+    }
+  }
+}
+
+/**
+ * 发起流式对话
+ * @param request 对话请求
+ * @param callbacks 事件回调
+ * @returns SSE 控制器（用于中止连接）
+ */
+export async function startStreamDialog(
+  request: DialogRequest,
+  callbacks: SSECallbacks
+): Promise<SSEController> {
+  const controller = new SSEController();
+
+  const urlString = getApiUrl('/api/dialog/stream');
+  const url = new URL(urlString);
+  const isHttps = url.protocol === 'https:';
+  const httpModule = isHttps ? https : http;
+
+  const body = JSON.stringify(request);
+
+  console.log(`[SSE] 开始流式对话: taskId=${request.taskId}, url=${urlString}`);
+
+  return new Promise((resolve, reject) => {
+    const options: http.RequestOptions = {
+      hostname: url.hostname,
+      port: url.port || (isHttps ? 443 : 80),
+      path: url.pathname + url.search,
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'Accept': 'text/event-stream',
+        'Cache-Control': 'no-cache',
+        'Content-Length': Buffer.byteLength(body)
+      }
+    };
+
+    const req = httpModule.request(options, (res) => {
+      // 检查响应状态
+      if (res.statusCode !== 200) {
+        let errorBody = '';
+        res.on('data', chunk => errorBody += chunk);
+        res.on('end', () => {
+          const error = new Error(`SSE 连接失败: ${res.statusCode} ${errorBody}`);
+          callbacks.onError?.({ message: error.message });
+          reject(error);
+        });
+        return;
+      }
+
+      // 连接成功
+      console.log('[SSE] 连接已建立');
+      controller.setConnected(true);
+      callbacks.onOpen?.();
+      resolve(controller);
+
+      // 创建 SSE 解析器
+      const parser = createParser({
+        onEvent: (event) => {
+          const eventType = event.event as SSEEventType;
+          const eventData = event.data;
+
+          if (!eventData) {
+            console.log(`[SSE] 收到空事件: ${eventType}`);
+            return;
+          }
+
+          try {
+            const data = JSON.parse(eventData);
+            console.log(`[SSE] 收到事件: ${eventType}`, data);
+
+            // 分发事件到对应回调
+            dispatchEvent(eventType, data, callbacks);
+          } catch (e) {
+            console.error(`[SSE] 解析事件数据失败: ${eventData}`, e);
+          }
+        }
+      });
+
+      // 设置编码
+      res.setEncoding('utf8');
+
+      // 处理数据流
+      res.on('data', (chunk: string) => {
+        if (!controller.aborted) {
+          console.log('[SSE] 收到原始数据块:', chunk.substring(0, 200));
+          parser.feed(chunk);
+        }
+      });
+
+      // 处理连接关闭
+      res.on('end', () => {
+        console.log('[SSE] 连接已关闭');
+        controller.setConnected(false);
+        callbacks.onClose?.();
+      });
+
+      // 处理错误
+      res.on('error', (err) => {
+        if (!controller.aborted) {
+          console.error('[SSE] 响应错误:', err);
+          controller.setConnected(false);
+          callbacks.onError?.({ message: err.message });
+        }
+      });
+    });
+
+    // 保存请求引用用于中止
+    controller.setRequest(req);
+
+    // 处理请求错误
+    req.on('error', (err) => {
+      if (!controller.aborted) {
+        console.error('[SSE] 请求错误:', err);
+        controller.setConnected(false);
+        callbacks.onError?.({ message: err.message });
+        reject(err);
+      }
+    });
+
+    // 处理超时
+    const { timeout } = getConfig();
+    req.setTimeout(timeout, () => {
+      if (!controller.aborted) {
+        console.error('[SSE] 请求超时');
+        controller.abort();
+        const error = new Error('请求超时');
+        callbacks.onError?.({ message: error.message });
+        reject(error);
+      }
+    });
+
+    // 发送请求体
+    req.write(body);
+    req.end();
+  });
+}
+
+/**
+ * 分发 SSE 事件到对应回调
+ */
+function dispatchEvent(
+  eventType: SSEEventType,
+  data: unknown,
+  callbacks: SSECallbacks
+): void {
+  switch (eventType) {
+    case 'text_delta':
+      callbacks.onTextDelta?.(data as TextDeltaEvent);
+      break;
+    case 'tool_call':
+      callbacks.onToolCall?.(data as ToolCallRequest);
+      break;
+    case 'tool_start':
+      callbacks.onToolStart?.(data as ToolStartEvent);
+      break;
+    case 'tool_complete':
+      callbacks.onToolComplete?.(data as ToolCompleteEvent);
+      break;
+    case 'tool_error':
+      callbacks.onToolError?.(data as ToolErrorEvent);
+      break;
+    case 'ask_user':
+      callbacks.onAskUser?.(data as AskUserEvent);
+      break;
+    case 'complete':
+      callbacks.onComplete?.(data as CompleteEvent);
+      break;
+    case 'error':
+      callbacks.onError?.(data as ErrorEvent);
+      break;
+    case 'warning':
+      callbacks.onWarning?.(data as WarningEvent);
+      break;
+    case 'notification':
+      callbacks.onNotification?.(data as NotificationEvent);
+      break;
+    case 'depth_update':
+      callbacks.onDepthUpdate?.(data as DepthUpdateEvent);
+      break;
+    default:
+      console.log(`[SSE] 未知事件类型: ${eventType}`, data);
+  }
+}
+
+/**
+ * 生成任务ID
+ */
+export function generateTaskId(): string {
+  return `task-${Date.now()}-${Math.random().toString(36).substring(2, 8)}`;
+}