feat(application): add DocumentOperator.Application PDF signing contracts

DocumentOperator.Application/SignPdf/SignPdfCommand.cs

@@ -0,0 +1,22 @@
+using DocumentOperator.Application.Common.Dto;
+using DocumentOperator.Application.Common.Interfaces.Services;
+using MediatR;
+
+namespace DocumentOperator.Application.SignPdf;
+
+public sealed record SignPdfCommand : IRequest<byte[]>
+{
+    public required Stream InputPdf { get; init; }
+    public required PdfSignOptionsDto Options { get; init; }
+    public Stream? SignatureImage { get; init; }
+}
+
+public sealed class SignPdfCommandHandler(IPdfDigitalSignatureService signer) : IRequestHandler<SignPdfCommand, byte[]>
+{
+    public async Task<byte[]> Handle(SignPdfCommand command, CancellationToken cancellationToken)
+    {
+        using var output = new MemoryStream();
+        await signer.SignPdfAsync(command.InputPdf, output, command.Options, command.SignatureImage, cancellationToken);
+        return output.ToArray();
+    }
+}