Add AI parent meetings after a class last lesson.

Class teachers rarely keep the homeroom; invited parents walk onto the map, opinions nudge, then parents leave OffCampus. No player schedule API.

src/HSchool.Content/PeopleDefValidator.cs

@@ -684,6 +684,24 @@ internal static class PeopleDefValidator
                 $"BehaviorDef '{behavior.DefName}' directorHearingMinutes must be positive.");
         }
 
+        if (behavior.ParentMeetingChance is < 0f or > 1f)
+        {
+            throw new ContentLoadException(
+                $"BehaviorDef '{behavior.DefName}' parentMeetingChance must be 0–1.");
+        }
+
+        if (behavior.ParentMeetingAttendanceFraction is < 0f or > 1f)
+        {
+            throw new ContentLoadException(
+                $"BehaviorDef '{behavior.DefName}' parentMeetingAttendanceFraction must be 0–1.");
+        }
+
+        if (behavior.ParentMeetingMinutes <= 0f)
+        {
+            throw new ContentLoadException(
+                $"BehaviorDef '{behavior.DefName}' parentMeetingMinutes must be positive.");
+        }
+
         if (behavior.LessonMarkMax < 0)
         {
             throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' lessonMarkMax cannot be negative.");