feat(simulation): integrate knowledge graph into observer snapshot (#366)

VisibleEntity now carries relationship state (D-033 entity color) and
observation type (Visible vs Remembered). compute_observer_snapshot
queries the player's KnowledgeGraph to overlay relationship data on
visible entities and include remembered (not-in-LOS) entities as fog
ghosts at their last known position. Regenerated msgpack fixtures.

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

server/src/bridge/mod.rs

@@ -89,6 +89,8 @@ pub fn generate_snapshot(
             z,
             kind,
             visibility: VisibilitySector::Forward,
+            relationship: RelationshipState::Unknown,
+            observation: EntityVisibility::Visible,
         });
     }
 

server/src/bridge/types.rs

@@ -5,6 +5,7 @@
 use bevy_ecs::prelude::*;
 use serde::{Deserialize, Serialize};
 
+pub use crate::knowledge::types::{EntityVisibility, KnowledgeConfidence, RelationshipState};
 pub use crate::simulation::time::DayPhase;
 
 /// The ONLY data structure crossing the client-server boundary (D-020)
@@ -95,6 +96,14 @@ pub struct VisibleEntity {
     pub kind: EntityKind,
     /// Which vision cone sector this entity falls in (D-015)
     pub visibility: VisibilitySector,
+    /// Relationship state for D-033 entity color rendering.
+    /// Unknown for entities not yet in the knowledge graph.
+    #[serde(default)]
+    pub relationship: RelationshipState,
+    /// Whether this entity is currently visible or remembered from knowledge.
+    /// Visible = in LOS right now. Remembered = known but not in LOS.
+    #[serde(default)]
+    pub observation: EntityVisibility,
 }
 
 /// Category of visible entity