feat(i18n): 添加主页国际化支持并优化语言切换

- 添加主页相关翻译键（guest, onlineCount, loading等）
- 修改主页使用 $lang 动态显示文本
- 分类名称改为使用 nameKey 映射到语言文件
- 添加 URL 参数语言检测（App.vue onLaunch）
- GamePortrait 返回时保留语言参数

支持语言：cn, tw, en, yn, kr, tl, in

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

language/en.js

@@ -38,6 +38,16 @@ var en = {
   buyu: "Fishing",
   qipai: "Slots",
 
+  // Home page
+  guest: "Guest",
+  onlineCount: "Online",
+  loading: "Loading...",
+  maxLimit: "Max",
+  minLimit: "Min",
+  betting: "Betting",
+  dealing: "Dealing",
+  preparing: "Preparing",
+
   recharge: "Recharge",
   rechargeWithdrawNetwork: "Recharge / Withdraw Network",
   pleaseChoose: "Please Choose",