feat: добавил эндпоинт для получения статистики админского дашборда

backend/UniVerse.Infrastructure/Services/UserService.cs

@@ -74,6 +74,17 @@ public class UserService : IUserService
         );
     }
 
+    public async Task<AdminDashboardStatsDto> GetAdminDashboardStatsAsync()
+    {
+        var usersCount = await _db.Users
+            .CountAsync(user => !user.Roles.Any(role => role.Role == UserRole.Teacher));
+        var lecturesCount = await _db.Lectures.CountAsync();
+        var enrollmentsCount = await _db.LectureEnrollments.CountAsync();
+        var pendingReviewsCount = await _db.Reviews.CountAsync(review => review.LlmStatus == ReviewLlmStatus.Pending);
+
+        return new AdminDashboardStatsDto(usersCount, lecturesCount, enrollmentsCount, pendingReviewsCount);
+    }
+
     public async Task<PagedResult<LectureDto>> GetEnrollmentsAsync(int id, PaginationRequest pagination)
     {
         if (!await _db.Users.AnyAsync(u => u.Id == id))