add simplification steps

csharp-fp1/Application/AccountApplicationService.cs

@@ -0,0 +1,17 @@
+using CsharpFp1.Domain;
+
+namespace CsharpFp1.Application;
+
+public static class AccountApplicationService
+{
+    public static void WithdrawMoney(IAccountRepository repository, Guid accountId, decimal amount)
+    {
+        var account =
+            repository.GetById(new AccountId(accountId))
+            ?? throw new InvalidOperationException("Account not found.");
+
+        account.Withdraw(new Money(amount));
+
+        repository.Save(account);
+    }
+}