models + fix DTO

PF3/Models/SoundTimecode.cs

@@ -0,0 +1,22 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace PF3.Models;
+
+public class SoundTimecode
+{
+    [Key] public int Id { get; set; }
+
+    [Required]
+    public int ShowId { get; set; }
+    public Show? Show { get; set; }
+
+    [Required]
+    public int SoundId { get; set; }
+    public Sound? Sound { get; set; }
+
+    [Required, Range(0, int.MaxValue)]
+    public int Start { get; set; }
+
+    [Required, Range(0, int.MaxValue)]
+    public int End { get; set; }
+}