phsl / new-api

- Add GET /api/data/users endpoint for user-grouped quota data (admin only)
- Add user consumption ranking (horizontal bar, top 10) and user consumption
  trend (area chart) tabs visible only to admin users
- Fix mislabeled "消耗趋势" tab to "调用趋势" (shows call counts, not quota)
- Add processUserData helper for user ranking and trend data extraction
- Add i18n keys for new tabs across all 7 locales