Add CloseWorkflowReqBody and CloseWorkflowReqResponse

Introduce two new classes in the DigitalData.TaskFlow.API.Models namespace to handle workflow closure requests and responses.

- CloseWorkflowReqBody.cs:
  - Added CloseWorkflowReqBody class with properties:
    - ClosingMethodId: int, mapped to "closing_method_id".
    - Comment: nullable string.
    - RejectionReasonId: nullable byte, mapped to "rejection_reason_id".

- CloseWorkflowReqResponse.cs:
  - Added CloseWorkflowReqResponse class with Meta property:
    - Meta: List of CloseWorkflowResult, initialized to an empty list.

src/presentation/DigitalData.TaskFlow.API/Models/CloseWorkflowReqBody.cs

@@ -0,0 +1,26 @@
+using System.Text.Json.Serialization;
+
+namespace DigitalData.TaskFlow.API.Models;
+
+/// <summary>
+/// 
+/// </summary>
+public class CloseWorkflowReqBody
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonPropertyName("closing_method_id")]
+    public int ClosingMethodId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? Comment { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonPropertyName("rejection_reason_id")]
+    public byte? RejectionReasonId { get; init; }
+}

src/presentation/DigitalData.TaskFlow.API/Models/CloseWorkflowReqResponse.cs

@@ -0,0 +1,14 @@
+using DigitalData.TaskFlow.Application.Features.Workflows.Commands;
+
+namespace DigitalData.TaskFlow.API.Models;
+
+/// <summary>
+/// 
+/// </summary>
+public class CloseWorkflowReqResponse
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public List<CloseWorkflowResult> Meta { get; init; } = [];
+}