Refactored idempotency check to observe completed status

LiteCharms.Features.MidrandBooks/Payments/PaymentService.cs

@@ -123,8 +123,7 @@ public sealed class PaymentService(IDbContextFactory<MidrandBooksDbContext> cont
             await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);
 
             var exists = await context.Ledger.AnyAsync(l =>
-                l.OrderId == orderId &&
-                l.PaymentId == paymentId, cancellationToken);
+                l.OrderId == orderId && l.PaymentId == paymentId && l.Status == LedgerStatuses.Completed, cancellationToken);
 
             return Result.Ok(exists);
         }