feat(Documents) Notes/Docs page improvements and warning cleanup

Model/Notes/NoteSectionModel.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Model.Notes;
+
+public class NoteSectionModel
+{
+    [Key] public int Id { get; set; }
+
+    public string Name { get; set; }
+
+    [NotMapped]
+    public virtual ICollection<NoteContentModel> NoteContentModels { get; set; } = new List<NoteContentModel>();
+}