Feature: Add token validation, basic confirmation workflow (#164)

src/Core/Service/Service.Auth/ConfirmationService.cs

@@ -0,0 +1,34 @@
+
+using Domain.Exceptions;
+using Infrastructure.Repository.Auth;
+
+namespace Service.Auth;
+
+public class ConfirmationService(
+    IAuthRepository authRepository,
+    ITokenService tokenService
+) : IConfirmationService
+{
+   public async Task<ConfirmationServiceReturn> ConfirmUserAsync(
+       string confirmationToken
+   )
+   {
+      var validatedToken = await tokenService.ValidateConfirmationTokenAsync(
+          confirmationToken
+      );
+
+      var user = await authRepository.ConfirmUserAccountAsync(
+          validatedToken.UserId
+      );
+
+      if (user == null)
+      {
+         throw new UnauthorizedException("User account not found");
+      }
+
+      return new ConfirmationServiceReturn(
+          DateTime.UtcNow,
+          user.UserAccountId
+      );
+   }
+}