Add lesson whispers, teacher catch chance, and after-bell teacher talk.

Whispering cuts lesson skill gain from BehaviorDef; a teacher in the room may interrupt into a discipline circle, and pedagogy scales the pupil's opinion of the teacher.

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

src/HSchool.Simulation/PresenceSystem.cs

@@ -333,7 +333,7 @@ internal static class PresenceSystem
             : slot.Kind == DaySlotKind.Lesson && lessons.Any(lesson => lesson.Period == slot.Index);
         if (activity.IsActive && TalkActions.IsTalk(activity.ActionId))
         {
-            if (!bound)
+            if (!bound || TalkActions.IsWhisper(activity.ActionId))
             {
                 return null;
             }
@@ -432,7 +432,48 @@ internal static class PresenceSystem
             presence = PresenceStepper.StartWalk(presence, walks, decision.WalkTo, headingHome: false);
         }
 
-        return decision.StartAction is not null && !activity.IsActive ? decision.StartAction : null;
+        if (decision.StartAction is not null && !activity.IsActive)
+        {
+            return decision.StartAction;
+        }
+
+        if (!activity.IsActive
+            && decision.WalkTo is null
+            && ShouldStartWhisper(school, person, state))
+        {
+            return TalkActions.Whisper;
+        }
+
+        return null;
+    }
+
+    private static bool ShouldStartWhisper(School school, Person person, ActorState state)
+    {
+        if (!state.BoundToLesson
+            || !person.IsStudent
+            || state.IsWalking
+            || state.NodeId is null
+            || state.DutyRoom is null
+            || !state.NodeId.Equals(state.DutyRoom, StringComparison.Ordinal))
+        {
+            return false;
+        }
+
+        var location = school.Map?.NodeDef(state.NodeId);
+        if (location is null || !location.Equals("Classroom", StringComparison.Ordinal))
+        {
+            return false;
+        }
+
+        var rules = school.Catalog?.BehaviorRules;
+        var chance = (rules?.WhisperStartChance ?? 0.12f) * TalkCircles.Initiative(person.Traits, school.Catalog!);
+        var roll = TalkCircles.Roll01(
+            Seed.Mix(
+                school.PeopleSeed,
+                person.Id,
+                DateOnly.FromDateTime(school.Clock.Time).DayNumber,
+                Seed.WhisperSalt + (school.Clock.Time.Minute / 2)));
+        return TalkCircles.WhisperCaught(roll, chance, 0.5f, 1f);
     }
 
     private static Dictionary<(string Node, string Thing), int> SnapshotOccupied(School school, string exceptId)