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

DocumentOperator.Application/Common/Interfaces/Services/IPdfDigitalSignatureService.cs

@@ -0,0 +1,29 @@
+using DocumentOperator.Application.Common.Dto;
+
+namespace DocumentOperator.Application.Common.Interfaces.Services;
+
+/// <summary>
+/// Defines PDF digital-signing operations for the application boundary.
+/// </summary>
+public interface IPdfDigitalSignatureService
+{
+    /// <summary>
+    /// Creates a digital signature for the provided PDF bytes and returns
+    /// a new signed PDF document.
+    /// </summary>
+    /// <param name="inputPdf">Source PDF content stream.</param>
+    /// <param name="outputPdf">Destination stream for signed PDF output.</param>
+    /// <param name="options">Optional signing options that map to PDF signature metadata fields.</param>
+    /// <param name="image">Optional image stream for signature appearance.</param>
+    /// <param name="cancellationToken">Cancellation token for cooperative cancellation.</param>
+    Task SignPdfAsync(Stream inputPdf, Stream outputPdf, PdfSignOptionsDto? options = null, Stream? image = null, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Checks whether the provided PDF contains signature field(s) and whether
+    /// those signatures are cryptographically valid.
+    /// </summary>
+    /// <param name="inputPdf">PDF content stream to inspect.</param>
+    /// <param name="cancellationToken">Cancellation token for cooperative cancellation.</param>
+    /// <returns>A structured result containing signature presence and per-signature details.</returns>
+    Task<PdfSignatureCheckResultDto> CheckPdfSignatureAsync(Stream inputPdf, CancellationToken cancellationToken = default);
+}

DocumentOperator.Application/Common/Interfaces/Services/IPkcs11SelfTestStatusProvider.cs

@@ -0,0 +1,8 @@
+using DocumentOperator.Application.Common.Dto;
+
+namespace DocumentOperator.Application.Common.Interfaces.Services;
+
+public interface IPkcs11SelfTestStatusProvider
+{
+    Pkcs11SelfTestStatusDto GetStatus();
+}