feat: add a Tools page printer for note merge and print presets

Chapter officers can merge a markdown note onto filtered students, teams, or events and save the recipe. Extra student-note columns are additional fields (any ## … fields heading) so they work as print tokens whether imported or typed by hand.

Co-authored-by: Cursor <cursoragent@cursor.com>

Core/Entities/PrintPreset.cs

@@ -0,0 +1,26 @@
+using System.ComponentModel.DataAnnotations;
+using Core.Printing;
+
+namespace Core.Entities;
+
+/// <summary>
+/// Saved page-printer recipe: template note, entity type, and filters. Merged output is not stored.
+/// </summary>
+public class PrintPreset
+{
+    public int Id { get; set; }
+
+    [Required]
+    [StringLength(100)]
+    public string Name { get; set; } = null!;
+
+    public int NoteId { get; set; }
+
+    public Note Note { get; set; } = null!;
+
+    public PrintEntityType EntityType { get; set; }
+
+    public string FiltersJson { get; set; } = "{}";
+
+    public DateTime UpdatedAt { get; set; }
+}