Добавил слой Application

backend/UniVerse.Application/Interfaces/IAchievementService.cs

@@ -0,0 +1,12 @@
+using UniVerse.Application.DTOs.Achievements;
+
+namespace UniVerse.Application.Interfaces;
+
+public interface IAchievementService
+{
+    Task<List<AchievementDto>> GetAllAsync();
+    Task<AchievementDto> GetByIdAsync(int id);
+    Task<AchievementDto> CreateAsync(CreateAchievementRequest request);
+    Task<AchievementDto> UpdateAsync(int id, UpdateAchievementRequest request);
+    Task DeleteAsync(int id);
+}