feat(server): 添加游戏服务器框架 | add game server framework (#366)

**@esengine/server** - 游戏服务器框架 | Game server framework
- 文件路由系统 | File-based routing
- Room 生命周期 (onCreate, onJoin, onLeave, onTick, onDispose)
- @onMessage 装饰器 | Message handler decorator
- 玩家管理与断线处理 | Player management with auto-disconnect
- 内置 JoinRoom/LeaveRoom API | Built-in room APIs
- defineApi/defineMsg 类型安全辅助函数 | Type-safe helpers

**create-esengine-server** - CLI 脚手架工具 | CLI scaffolding
- 生成 shared/server/client 项目结构 | Project structure
- 类型安全的协议定义 | Type-safe protocol definitions
- 包含 GameRoom 示例 | Example implementation

**其他 | Other**
- 删除旧的 network-server 包 | Remove old network-server
- 更新服务器文档 | Update server documentation

packages/framework/server/module.json

@@ -0,0 +1,21 @@
+{
+  "id": "server",
+  "name": "@esengine/server",
+  "globalKey": "server",
+  "displayName": "Game Server",
+  "description": "Game server framework with file-based routing | 基于文件路由的游戏服务器框架",
+  "version": "1.0.0",
+  "category": "Network",
+  "icon": "Server",
+  "tags": ["server", "rpc", "websocket", "network"],
+  "isCore": false,
+  "defaultEnabled": false,
+  "isEngineModule": true,
+  "canContainContent": false,
+  "platforms": ["nodejs"],
+  "dependencies": ["rpc"],
+  "exports": {
+    "functions": ["createServer", "defineApi", "defineMsg"]
+  },
+  "outputPath": "dist/index.js"
+}