feat: write a dto in a separate project

ApiDto/Responses/GroupResponse.cs

@@ -0,0 +1,22 @@
+namespace Mirea.Api.Dto.Responses;
+
+/// <summary>
+/// Represents basic information about a group.
+/// </summary>
+public class GroupResponse
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the group.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the group.
+    /// </summary>
+    public required string Name { get; set; }
+
+    /// <summary>
+    /// Gets or sets the unique identifier of the faculty to which the group belongs (optional).
+    /// </summary>
+    public int? FacultyId { get; set; }
+}