feat: 新增移动客户端（iOS + Android）

- 新增 mobile/ 项目：React Native + Expo
- 5个核心页面：连接服务器、房间列表、创建房间、加入房间、设置
- Tab 导航 + Minecraft 风格深色 UI
- 房间搜索/筛选（名称、房间号、房主、版本类型）
- 15秒自动刷新房间列表
- 设置持久化（AsyncStorage）
- EAS Build 配置（云端构建 iOS/Android）
- 完整 README 含构建指南
- 更新顶层 README 为三项目全平台架构

mobile/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "funconnect-mobile",
+  "version": "1.1.0",
+  "description": "FunConnect - Minecraft 联机客户端 (iOS & Android)",
+  "main": "index.js",
+  "scripts": {
+    "start": "expo start",
+    "android": "expo run:android",
+    "ios": "expo run:ios",
+    "build:android": "eas build --platform android",
+    "build:ios": "eas build --platform ios",
+    "build:all": "eas build --platform all"
+  },
+  "dependencies": {
+    "expo": "~50.0.0",
+    "expo-status-bar": "~1.11.1",
+    "expo-clipboard": "~5.0.1",
+    "expo-constants": "~15.4.5",
+    "react": "18.2.0",
+    "react-native": "0.73.4",
+    "react-native-safe-area-context": "4.8.2",
+    "react-native-screens": "~3.29.0",
+    "@react-navigation/native": "^6.1.9",
+    "@react-navigation/bottom-tabs": "^6.5.11",
+    "@react-native-async-storage/async-storage": "1.21.0",
+    "axios": "^1.6.2"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.20.0",
+    "@types/react": "~18.2.45",
+    "typescript": "^5.3.0"
+  },
+  "private": true
+}