Misc bunch of changes (#2815)

API/DTOs/Progress/ProgressDto.cs

@@ -0,0 +1,26 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+
+namespace API.DTOs.Progress;
+#nullable enable
+
+public class ProgressDto
+{
+    [Required]
+    public int VolumeId { get; set; }
+    [Required]
+    public int ChapterId { get; set; }
+    [Required]
+    public int PageNum { get; set; }
+    [Required]
+    public int SeriesId { get; set; }
+    [Required]
+    public int LibraryId { get; set; }
+    /// <summary>
+    /// For EPUB reader, this can be an optional string of the id of a part marker, to help resume reading position
+    /// on pages that combine multiple "chapters".
+    /// </summary>
+    public string? BookScrollId { get; set; }
+
+    public DateTime LastModifiedUtc { get; set; }
+}