feat(dashboard): add admin user analytics and fix chart labels

- 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

web/src/i18n/locales/zh-CN.json

@@ -2314,6 +2314,10 @@
     "调用次数": "调用次数",
     "调用次数分布": "调用次数分布",
     "调用次数排行": "调用次数排行",
+    "调用趋势": "调用趋势",
+    "模型排行": "模型排行",
+    "用户消耗排行": "用户消耗排行",
+    "用户消耗趋势": "用户消耗趋势",
     "调试信息": "调试信息",
     "谨慎": "谨慎",
     "警告": "警告",