fix(checkin): prevent visual flicker when loading check-in component

- Add initialLoaded state to track first data load completion
- Set isCollapsed to null initially, determined after data loads
- Show loading state on button and description text before data arrives
- Remove auto-collapse effect that caused visual flicker
- Add i18n translations for loading states (en/fr/ja/ru/vi/zh)

Fixes issue where component would collapse/expand after data loads,
causing visual flicker when navigating to personal settings page.

web/src/i18n/locales/en.json

@@ -2192,6 +2192,8 @@
     "每日签到可获得随机额度奖励": "Daily check-in rewards random quota",
     "今日已签到": "Checked in today",
     "立即签到": "Check in now",
+    "加载中...": "Loading...",
+    "正在加载签到状态...": "Loading check-in status...",
     "获取签到状态失败": "Failed to get check-in status",
     "签到成功！获得": "Check-in successful! Received",
     "签到失败": "Check-in failed",