feat(BurnPdfCommandHandler): implement AddInkAnnotation for Annotation parameter

- Added implementation for AddInkAnnotation(Annotation) to handle ink annotations from Annotation objects.
- Retained existing AddInkAnnotation(int, string) method for backward compatibility.
- Refactored PDF burning logic to support both Annotation-based and JSON-based annotations.

EnvelopeGenerator.Application/Pdf/BurnPdfCommand.cs

@@ -347,10 +347,23 @@ public class BurnPdfCommandHandler : IRequestHandler<BurnPdfCommand>
             _manager.AddFreeHandAnnot(oColor, oPoints);
         }
     }
-
-    private void AddInkAnnotation(Annotation pAnnotation)
+        private void AddInkAnnotation(Annotation pAnnotation)
     {
-        throw new NotImplementedException();
+        var oSegments = pAnnotation.Lines?.Points;
+        var oColor = ColorTranslator.FromHtml(pAnnotation.StrokeColor ?? "#000000");
+        _manager.SelectPage(pAnnotation.PageIndex + 1);
+
+        if (oSegments is null)
+            return;
+
+        foreach (var oSegment in oSegments)
+        {
+            var oPoints = oSegment
+                .Select(ToPointF)
+                .ToArray();
+
+            _manager.AddFreeHandAnnot(oColor, oPoints);
+        }
     }
 
     #region Helpers