Add TryExtract method to SwissQrCodeResult record

Replaced the fully qualified reference to
`DocumentService.Application.Common.DTOs.PdfValidationResult.IsValid`
with the simpler `PdfValidationResult.IsValid`.

Added a `TryExtract` method to the `SwissQrCodeResult` record to
improve code readability and usability. The method follows the
standard `TryXxx` pattern, allowing for an `if/else` branch
instead of a direct null-check on the `QrCode` property. It
returns `true` if the PDF was valid and a Swiss QR Code was
successfully extracted, and `false` otherwise.

DocumentService.Client/Models/Results/SwissQrCodeResult.cs

@@ -13,9 +13,31 @@ namespace DocumentService.Client.Models.Results;
 /// </param>
 /// <param name="Validation">
 /// PDF validation result. Always populated regardless of whether extraction succeeded.
-/// Use <see cref="DocumentService.Application.Common.DTOs.PdfValidationResult.IsValid"/>
+/// Use <see cref="PdfValidationResult.IsValid"/>
 /// to determine whether the extraction was attempted.
 /// </param>
 public record SwissQrCodeResult(
     SwissQrCodeExtractionResult? QrCode,
-    PdfValidationResult Validation);
+    PdfValidationResult Validation)
+{
+    /// <summary>
+    /// Optional convenience method for code readability. Follows the standard
+    /// <c>TryXxx</c> pattern (e.g. <see cref="int.TryParse(string, out int)"/>,
+    /// <see cref="Dictionary{TKey,TValue}.TryGetValue"/>).
+    /// Use it when you prefer an <c>if/else</c> branch over a null-check on <see cref="QrCode"/>;
+    /// it is not required – both approaches are equivalent.
+    /// </summary>
+    /// <param name="qrCode">
+    /// When this method returns <c>true</c>, contains the extracted QR Code data.
+    /// When this method returns <c>false</c>, this value is <c>null</c> and must not be used.
+    /// </param>
+    /// <returns>
+    /// <c>true</c> if the PDF was valid and a Swiss QR Code was successfully extracted;
+    /// <c>false</c> otherwise.
+    /// </returns>
+    public bool TryExtract(out SwissQrCodeExtractionResult qrCode)
+    {
+        qrCode = QrCode ?? null!;
+        return Validation.IsValid && QrCode is not null;
+    }
+}