Refactor DTOs for improved structure and documentation

Transitioned from records to classes for flexibility, added XML documentation for clarity, and updated property definitions to use standard getters and setters. Introduced the `required` keyword for essential properties, removed unnecessary constructors, and enhanced property descriptions for better readability. Additionally, overridden `GetHashCode` in `ReceiverReadDto` for proper collection behavior.

EnvelopeGenerator.Application/DTOs/UserReceiverDto.cs

@@ -1,15 +1,46 @@
 using DigitalData.Core.Abstractions;
 using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.DTOs;
+
+/// <summary>
+/// Data Transfer Object representing a user receiver with associated details.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class UserReceiverDto : IUnique<int>
 {
-    [ApiExplorerSettings(IgnoreApi = true)]
-    public record UserReceiverDto(
-        int Id,
-        int UserId,
-        int ReceiverId,
-        string Name,
-        string CompanyName,
-        string JobTitle,
-        DateTime AddedWhen) : IUnique<int>;
+    /// <summary>
+    /// Gets or sets the unique identifier of the user receiver.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the user associated with the receiver.
+    /// </summary>
+    public int UserId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the receiver.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the receiver.
+    /// </summary>
+    public string Name { get; set; }
+
+    /// <summary>
+    /// Gets or sets the company name of the receiver.
+    /// </summary>
+    public string CompanyName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the job title of the receiver.
+    /// </summary>
+    public string JobTitle { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the user receiver was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
 }