Add lesson marks 2-5 from lesson quality once per slot.

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

src/HSchool.Content/PeopleDefValidator.cs

@@ -665,6 +665,45 @@ internal static class PeopleDefValidator
                 throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' offenseMemoryKinds cannot contain empty ids.");
             }
         }
+
+        if (behavior.LessonMarkMax < 0)
+        {
+            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' lessonMarkMax cannot be negative.");
+        }
+
+        if (behavior.LessonMarkWhenNoTeacher is { } absent
+            && absent is < 2 or > 5)
+        {
+            throw new ContentLoadException(
+                $"BehaviorDef '{behavior.DefName}' lessonMarkWhenNoTeacher must be 2–5 or null.");
+        }
+
+        if (behavior.LessonMarkThresholds.Count > 0)
+        {
+            if (behavior.LessonMarkThresholds.Count != 3)
+            {
+                throw new ContentLoadException(
+                    $"BehaviorDef '{behavior.DefName}' lessonMarkThresholds must list three floors (5, 4, 3).");
+            }
+
+            float? previous = null;
+            foreach (var floor in behavior.LessonMarkThresholds)
+            {
+                if (floor is < 0f or > 1f)
+                {
+                    throw new ContentLoadException(
+                        $"BehaviorDef '{behavior.DefName}' lessonMarkThresholds must be 0–1.");
+                }
+
+                if (previous is { } prior && floor > prior)
+                {
+                    throw new ContentLoadException(
+                        $"BehaviorDef '{behavior.DefName}' lessonMarkThresholds must be descending.");
+                }
+
+                previous = floor;
+            }
+        }
     }
 
     private static void ValidateTopic(TopicDef topic, DefCatalog catalog)

src/HSchool.Content/PeopleDefs.cs

@@ -584,6 +584,30 @@ public sealed class BehaviorDef : Def
         "reprimand",
     ];
 
+    /// <summary>
+    /// How many recent lesson marks a person keeps. Oldest drop first. Zero disables marks.
+    /// </summary>
+    public int LessonMarkMax { get; init; } = 40;
+
+    /// <summary>
+    /// Inclusive quality floors for marks 5, 4, 3 (descending). Below the last → 2.
+    /// Empty falls back to <see cref="DefaultLessonMarkThresholds"/>.
+    /// </summary>
+    public IReadOnlyList<float> LessonMarkThresholds { get; init; } = DefaultLessonMarkThresholds;
+
+    /// <summary>
+    /// Mark written when the assigned teacher is not standing in the lesson room.
+    /// Null = skip the mark (no grade for air). Vanilla writes 2.
+    /// </summary>
+    public int? LessonMarkWhenNoTeacher { get; init; } = 2;
+
+    public static IReadOnlyList<float> DefaultLessonMarkThresholds { get; } =
+    [
+        0.85f,
+        0.6f,
+        0.35f,
+    ];
+
     public static IReadOnlyList<OpinionBand> DefaultOpinionBands { get; } =
     [
         new() { Min = 70, Id = "OpinionCloseFriend" },