feat: 完善 Server 层并添加 CLI 和 Web 前端

Server 层增强:
- 添加 Agent 适配层，支持动态加载 core 模块
- 实现 Token 认证机制，支持本地/远程模式
- WebSocket 集成 Agent 实时对话

CLI 模块 (packages/cli):
- serve 命令启动 HTTP Server
- attach 命令连接远程 Server
- API Client 封装

Web 前端 (packages/web):
- React 18 + Vite + Tailwind CSS
- 会话管理侧边栏
- WebSocket 实时聊天界面
- 流式消息显示

packages/web/src/api/client.ts

@@ -0,0 +1,96 @@
+/**
+ * API Client for Web
+ */
+
+export interface Session {
+  id: string;
+  name?: string;
+  createdAt: string;
+  updatedAt: string;
+  status: string;
+  messageCount: number;
+}
+
+export interface Message {
+  id: string;
+  role: 'user' | 'assistant' | 'system';
+  content: string;
+  timestamp: string;
+}
+
+export interface HealthStatus {
+  status: string;
+  timestamp: string;
+  agent: {
+    coreAvailable: boolean;
+  };
+  auth: {
+    enabled: boolean;
+    tokenCount: number;
+  };
+  stats: {
+    sessions: number;
+    websocket: { connections: number };
+    sse: { connections: number };
+  };
+}
+
+const API_BASE = '/api';
+
+async function request<T>(method: string, path: string, body?: unknown): Promise<T> {
+  const response = await fetch(`${API_BASE}${path}`, {
+    method,
+    headers: {
+      'Content-Type': 'application/json',
+    },
+    body: body ? JSON.stringify(body) : undefined,
+  });
+
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({ error: response.statusText }));
+    throw new Error(error.error || `HTTP ${response.status}`);
+  }
+
+  return response.json();
+}
+
+// Health
+export async function getHealth(): Promise<HealthStatus> {
+  return request('GET', '/../health');
+}
+
+// Sessions
+export async function listSessions(): Promise<{ success: boolean; data: Session[] }> {
+  return request('GET', '/sessions');
+}
+
+export async function createSession(name?: string): Promise<{ success: boolean; data: Session }> {
+  return request('POST', '/sessions', { name });
+}
+
+export async function getSession(id: string): Promise<{ success: boolean; data: Session }> {
+  return request('GET', `/sessions/${id}`);
+}
+
+export async function deleteSession(id: string): Promise<{ success: boolean }> {
+  return request('DELETE', `/sessions/${id}`);
+}
+
+// Messages
+export async function getMessages(sessionId: string): Promise<{ success: boolean; data: Message[] }> {
+  return request('GET', `/sessions/${sessionId}/messages`);
+}
+
+export async function sendMessage(
+  sessionId: string,
+  content: string
+): Promise<{ success: boolean; data: Message }> {
+  return request('POST', `/sessions/${sessionId}/messages`, { content });
+}
+
+// WebSocket
+export function createWebSocket(sessionId: string): WebSocket {
+  const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+  const host = window.location.host;
+  return new WebSocket(`${protocol}//${host}/api/ws/${sessionId}`);
+}