feat(simulation): dialogue pipeline, ContentSlug, and walk-away KG recording

Implement full dialogue selection pipeline (D-028): 4-layer filtering
engine with access tier, situation derivation, trust tier, and weighted
topic+mood scoring via SimRng. Add ContentSlug component for stable
content identity across save/load. Add walk-away KG recording with
IncompleteInteraction events per D-064 three-phase consequences. Bump
protocol to v8 with DialogueResponseEvent. Fixes #305, #427, #452.

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

server/src/knowledge/events.rs

@@ -29,6 +29,25 @@ pub enum KnowledgeEventType {
     },
     /// Entity left observer's LOS (downgrades from Direct).
     LeftLOS { target: Entity },
+    /// Observer walked away from an active interaction (D-064).
+    /// Records incompleteness in the target's known_attributes for future
+    /// dialogue/monologue consequences.
+    IncompleteInteraction {
+        target: Entity,
+        interaction_type: InteractionType,
+    },
+}
+
+/// Type of interaction for walk-away recording (D-064).
+/// Differentiates casual conversation from confrontation —
+/// future dialogue may react differently.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum InteractionType {
+    /// Normal Talk conversation.
+    Talk,
+    /// Confrontation (D-063). Walking away from confrontation
+    /// carries heavier consequences than casual talk.
+    Confront,
 }
 
 /// Resource: queue of pending knowledge events.
@@ -98,6 +117,24 @@ pub fn process_knowledge_events(
                     tracing::error!("LeftLOS target {:?} not in EntityRegistry", target);
                 }
             }
+            KnowledgeEventType::IncompleteInteraction {
+                target,
+                interaction_type,
+            } => {
+                if let Some(stable_id) = registry.to_stable(target) {
+                    observer_kg.record_incomplete_interaction(
+                        &stable_id,
+                        interaction_type,
+                        event.tick,
+                    );
+                    tracing::debug!(
+                        "Recorded incomplete {:?} interaction with {:?} at tick {}",
+                        interaction_type,
+                        stable_id,
+                        event.tick,
+                    );
+                }
+            }
         }
     }
 }