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/server/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@ai-assistant/server",
+  "version": "1.0.0",
+  "description": "HTTP Server for AI terminal assistant - REST API, WebSocket, SSE",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    }
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch",
+    "start": "bun run src/bin/server.ts",
+    "start:dev": "bun --watch run src/bin/server.ts",
+    "test": "vitest run",
+    "test:watch": "vitest"
+  },
+  "dependencies": {
+    "@ai-assistant/core": "workspace:*",
+    "hono": "^4.6.0",
+    "uuid": "^13.0.0",
+    "zod": "^4.1.13"
+  },
+  "devDependencies": {
+    "@types/bun": "^1.1.0",
+    "@types/node": "^22.0.0",
+    "@types/uuid": "^10.0.0",
+    "typescript": "^5.6.0",
+    "vitest": "^4.0.15"
+  }
+}