feat(simulation): extend monologue event generation with new triggers (#119)

Add observe_npc, hear_sound, observe_anomaly, witness_interaction, and
post_conversation triggers to monologue system. trigger_event_monologue
system fires after sound collection, NPC conversations, and walk-away.
Context tags (location, situation, character_state) populated for D-035
content pool matching. COOLDOWN_TICKS=300 anti-spam guard respected.
witness_interaction fires after overheard NPC-to-NPC conversation per
D-078. Voice sounds and ambient sounds correctly excluded from
hear_sound trigger.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/perception/interpretation.rs

@@ -68,6 +68,12 @@ impl ObservationEventQueue {
     pub fn is_empty(&self) -> bool {
         self.events.is_empty()
     }
+
+    /// Iterate over observation events without draining.
+    /// Used by monologue trigger system (#119) to react to previous-tick events.
+    pub fn iter(&self) -> impl Iterator<Item = &ObservationEvent> {
+        self.events.iter()
+    }
 }
 
 /// System: interpret visible snapshot against known routines and knowledge.

server/src/simulation/dialogue.rs

@@ -587,6 +587,7 @@ pub fn process_walk_away(
     mut commands: Commands,
     mut event_queue: ResMut<crate::knowledge::KnowledgeEventQueue>,
     mut trust_queue: ResMut<TrustEventQueue>,
+    mut post_conv_queue: ResMut<crate::simulation::monologue::PostConversationQueue>,
     time: Res<SimulationTime>,
     query: Query<(Entity, Option<&ActiveDialogue>, &WalkAwayRequest), With<PlayerCharacter>>,
     mut npc_mem_query: Query<Option<&mut InteractionMemory>>,
@@ -635,6 +636,9 @@ pub fn process_walk_away(
             });
         }
 
+        // Post-conversation monologue trigger (#119, D-035)
+        post_conv_queue.push(target);
+
         tracing::debug!(
             "Walk-away during {:?} dialogue at tick {} (started tick {}): \
              target {:?} → Tier2 animation + routine deviation",
@@ -1121,6 +1125,7 @@ mod tests {
         world.init_resource::<EntityRegistry>();
         world.init_resource::<crate::knowledge::KnowledgeEventQueue>();
         world.init_resource::<TrustEventQueue>();
+        world.init_resource::<crate::simulation::monologue::PostConversationQueue>();
         world
     }