feat(player): 新增长页面一键回到顶部按钮

- 在 MainLayout 主滚动区挂载浮动回顶按钮，投注列表与赛事详情等长页通用

- 滚动超过阈值后显示，支持平滑回顶与底部导航避让

- 补充中/英/马来语文案 common.back_to_top

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/player/src/i18n/en-US.ts

@@ -7,6 +7,7 @@ export default {
     no_more: 'No more',
     load_failed: 'Failed to load',
     retry: 'Retry',
+    back_to_top: 'Back to top',
   },
   nav: { home: 'Home', bet: 'Bet', bet_history: 'History', wallet: 'Wallet', profile: 'Profile' },
   home: {

apps/player/src/i18n/ms-MY.ts

@@ -7,6 +7,7 @@ export default {
     no_more: 'Tiada lagi',
     load_failed: 'Gagal dimuat',
     retry: 'Cuba lagi',
+    back_to_top: 'Kembali ke atas',
   },
   nav: {
     home: 'Laman Utama',

apps/player/src/i18n/zh-CN.ts

@@ -7,6 +7,7 @@ export default {
     no_more: '没有更多了',
     load_failed: '加载失败',
     retry: '重试',
+    back_to_top: '回到顶部',
   },
   nav: { home: '主页', bet: '投注', bet_history: '历史投注', wallet: '账单', profile: '我的' },
   home: {