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/mod.rs

@@ -12,7 +12,7 @@ pub mod graph;
 pub mod registry;
 pub mod types;
 
-pub use events::{KnowledgeEvent, KnowledgeEventQueue, KnowledgeEventType};
+pub use events::{InteractionType, KnowledgeEvent, KnowledgeEventQueue, KnowledgeEventType};
 pub use graph::KnowledgeGraph;
 pub use registry::{EntityRegistry, StableEntityId};
 pub use types::*;