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/Printing/PrintTokenMap.cs

@@ -0,0 +1,55 @@
+namespace Core.Printing;
+
+/// <summary>
+/// Builds a case-insensitive token map. Fill order is imported, then entity, then chapter
+/// so built-in names win over an imported column with the same name.
+/// </summary>
+public static class PrintTokenMap
+{
+    public static Dictionary<string, string> Create() =>
+        new(StringComparer.OrdinalIgnoreCase);
+
+    public static Dictionary<string, string> Build(
+        IReadOnlyDictionary<string, string?>? imported,
+        IReadOnlyDictionary<string, string?>? entity,
+        IReadOnlyDictionary<string, string?>? chapter)
+    {
+        var map = Create();
+        Apply(map, imported);
+        Apply(map, entity);
+        Apply(map, chapter);
+        return map;
+    }
+
+    public static void Apply(IDictionary<string, string> map, IReadOnlyDictionary<string, string?>? values)
+    {
+        if (values is null)
+            return;
+
+        foreach (var (key, value) in values)
+        {
+            if (string.IsNullOrWhiteSpace(key))
+                continue;
+            map[key] = Escape(value);
+        }
+    }
+
+    /// <summary>
+    /// Treats substituted values as plain text so they cannot change markdown or inject HTML.
+    /// </summary>
+    public static string Escape(string? value)
+    {
+        if (string.IsNullOrEmpty(value))
+            return string.Empty;
+
+        return value
+            .Replace("\\", "\\\\", StringComparison.Ordinal)
+            .Replace("*", "\\*", StringComparison.Ordinal)
+            .Replace("_", "\\_", StringComparison.Ordinal)
+            .Replace("`", "\\`", StringComparison.Ordinal)
+            .Replace("[", "\\[", StringComparison.Ordinal)
+            .Replace("]", "\\]", StringComparison.Ordinal)
+            .Replace("<", "&lt;", StringComparison.Ordinal)
+            .Replace(">", "&gt;", StringComparison.Ordinal);
+    }
+}