Add user stats page and refactor user navigation; replace modal with dedicated page for user statistics, enhancing routing and UI consistency. Update localization for new status keys in both English and Russian.

locales/ru.json

@@ -136,9 +136,12 @@
   "challenge.admin.users.stats.chains.progress": "Прогресс по цепочкам",
   "challenge.admin.users.stats.tasks": "Задания",
   "challenge.admin.users.stats.status.completed": "Завершено",
+  "challenge.admin.users.stats.status.accepted": "Принято",
   "challenge.admin.users.stats.status.needs_revision": "Доработка",
   "challenge.admin.users.stats.status.in_progress": "В процессе",
+  "challenge.admin.users.stats.status.pending": "Ожидает",
   "challenge.admin.users.stats.status.not_started": "Не начато",
+  "challenge.admin.users.stats.status.not_attempted": "Не пытался",
   "challenge.admin.users.stats.attempts": "Попыток:",
   "challenge.admin.users.stats.avg.check.time": "Среднее время проверки",
   "challenge.admin.users.stats.close": "Закрыть",