refactor(annotation): add lazy JSON deserialization for PSPDFKitInstantJSON

- Introduced Lazy<dynamic> field for deferred deserialization of PSPDFKitInstantJSON
- Added ExpandoObject property (PSPDFKitInstant) for dynamic access
- Updated handler to use ParsePSPDFKitInstant instead of ParsePSPDFKitInstantJSON
- Improved JsonSerializerOptions for case-insensitive property handling

EnvelopeGenerator.Application/Annotations/Commands/CreateAnnotationCommand.cs

@@ -5,6 +5,8 @@ using EnvelopeGenerator.Application.Common.Query;
 using EnvelopeGenerator.Domain.Entities;
 using MediatR;
 using Microsoft.EntityFrameworkCore;
+using System.Dynamic;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 
 namespace EnvelopeGenerator.Application.Annotations.Commands;
@@ -14,11 +16,36 @@ namespace EnvelopeGenerator.Application.Annotations.Commands;
 /// </summary>
 public record CreateAnnotationCommand : EnvelopeReceiverQueryBase, IRequest<IEnumerable<Signature>>
 {
+    /// <summary>
+    /// 
+    /// </summary>
+    public CreateAnnotationCommand()
+    {
+        _lazyPSPDFKitInstant = new(() =>
+        {
+            var options = new JsonSerializerOptions
+            {
+                PropertyNameCaseInsensitive = true,
+                PropertyNamingPolicy = null
+            };
+
+            return JsonSerializer.Deserialize<dynamic>(PSPDFKitInstantJSON, options) ?? new ExpandoObject();
+        });
+    }
+
     /// <summary>
     /// 
     /// </summary>
     [JsonIgnore]
     public string PSPDFKitInstantJSON { get; set; } = null!;
+
+    private readonly Lazy<dynamic> _lazyPSPDFKitInstant;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public ExpandoObject PSPDFKitInstant => _lazyPSPDFKitInstant.Value;
 }
 
 /// <summary>
@@ -72,7 +99,7 @@ public class CreateAnnotationCommandHandler : IRequestHandler<CreateAnnotationCo
 
         foreach (var element in elements)
         {
-            var annots = ParsePSPDFKitInstantJSON(request.PSPDFKitInstantJSON, element.Id)
+            var annots = ParsePSPDFKitInstant(request.PSPDFKitInstant, element.Id)
                 .Select(annot => new Annotation()
                 {
                     ElementId = element.Id,
@@ -90,10 +117,10 @@ public class CreateAnnotationCommandHandler : IRequestHandler<CreateAnnotationCo
     /// <summary>
     /// 
     /// </summary>
-    /// <param name="json"></param>
+    /// <param name="instant"></param>
     /// <param name="elementId"></param>
     /// <returns></returns>
-    public static Dictionary<string, string> ParsePSPDFKitInstantJSON(string json, int elementId)
+    public static Dictionary<string, string> ParsePSPDFKitInstant(ExpandoObject instant, int elementId)
     {
         Dictionary<string, string> annots = new();