feat: 重构为 Monorepo 架构并实现 HTTP Server

架构变更:
- 采用 pnpm workspaces 实现 Monorepo 结构
- 将现有代码迁移到 packages/core
- 新增 packages/server HTTP 服务层

Server 功能:
- REST API: 会话管理、工具管理、配置管理
- WebSocket: 实时双向通信支持
- SSE: 服务端事件推送
- Hono + Bun 作为运行时

API 端点:
- GET/POST /api/sessions - 会话 CRUD
- GET/POST /api/sessions/:id/messages - 消息管理
- GET /api/sessions/:id/events - SSE 事件流
- WS /api/ws/:sessionId - WebSocket 连接
- GET/POST /api/tools - 工具管理
- GET/PUT /api/config - 配置管理

packages/core/src/agent/presets/index.ts

@@ -0,0 +1,35 @@
+import type { AgentInfo } from '../types.js';
+import { generalAgent } from './general.js';
+import { exploreAgent } from './explore.js';
+import { codeReviewerAgent } from './code-reviewer.js';
+import { buildAgent } from './build.js';
+import { planAgent } from './plan.js';
+import { visionAgent } from './vision.js';
+
+/**
+ * 预设 Agent 集合
+ */
+export const presetAgents: Record<string, Omit<AgentInfo, 'name'>> = {
+  general: generalAgent,
+  explore: exploreAgent,
+  'code-reviewer': codeReviewerAgent,
+  build: buildAgent,
+  plan: planAgent,
+  vision: visionAgent,
+};
+
+/**
+ * 获取所有预设 Agent 名称
+ */
+export function getPresetAgentNames(): string[] {
+  return Object.keys(presetAgents);
+}
+
+/**
+ * 检查是否为预设 Agent
+ */
+export function isPresetAgent(name: string): boolean {
+  return name in presetAgents;
+}
+
+export { generalAgent, exploreAgent, codeReviewerAgent, buildAgent, planAgent, visionAgent };