fix(simulation): address PR #75 review — vision components, triangle validation, FNV-1a, KG gating

1. CRITICAL: spawn_template_npcs now inserts NpcVisionState, NpcMemory,
   PlayerAwareness on template-spawned NPCs — matches spawn_npc() pattern
   from PR #66. Without these, template NPCs were invisible to vision and
   awareness systems.

2. WARNING: generate_intra_template_triangles now calls validate_triangle_def
   before generating TriangleState — mirrors cross-template path. Updates
   test TriangleDefs and logistics-hub.yaml to pass all three quality checks
   (conflict viability, relationship coherence, interest divergence).

3. WARNING: state_hash in compute_observer_snapshot now uses FNV-1a instead
   of DefaultHasher — consistent with D-010 principle 4 and the pattern in
   TemplateId/TriangleId. Updates golden file for new hash value.

4. WARNING: TriangleCrisisEventWire.role_assignments now filtered against
   observer KnowledgeGraph — unknown NPCs redacted from wire event per
   D-010 principle 2 (information boundaries).

5. WARNING: ActiveTemplateInstances::insert now despawns previous instance
   entities before overwriting — prevents orphaned ECS entities.

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

server/src/perception/observer/mod.rs

@@ -9,7 +9,6 @@
 use bevy_ecs::prelude::*;
 use std::collections::BTreeSet;
 
-use std::hash::{Hash, Hasher};
 
 use crate::bridge::types::*;
 use crate::knowledge::graph::filter_by_access;
@@ -394,24 +393,40 @@ pub fn compute_observer_snapshot(
     let save_result = buffer.pending_save_result.take();
 
     // Drain triangle crisis events (#250) and convert to wire format.
-    let triangle_crisis_events = crisis_queue
+    // Drain triangle crisis events (#250) and filter role_assignments against
+    // observer KG (D-010 principle 2: information boundaries are universal).
+    // NPCs unknown to the observer are redacted from the wire event.
+    let triangle_crisis_events: Vec<TriangleCrisisEventWire> = crisis_queue
         .drain()
         .into_iter()
-        .map(TriangleCrisisEventWire::from)
+        .map(|e| {
+            let mut wire = TriangleCrisisEventWire::from(e);
+            wire.role_assignments.retain(|(_, npc_id)| {
+                observer_kg.knows_entity(&crate::knowledge::types::StableId(*npc_id))
+            });
+            wire
+        })
         .collect();
 
     // Compute state hash for desync detection (#85).
     // Hash inputs: player position (x, y, z), NPC count, tick number.
-    // Uses DefaultHasher for speed — not cryptographic, just comparison.
+    // Uses FNV-1a (64-bit) for determinism across Rust versions — DefaultHasher
+    // is explicitly prohibited by D-010 principle 4 (see template.rs module docs).
     let state_hash = {
-        let mut hasher = std::collections::hash_map::DefaultHasher::new();
-        time.tick.hash(&mut hasher);
-        observer_pos.x.hash(&mut hasher);
-        observer_pos.y.hash(&mut hasher);
-        observer_pos.z.hash(&mut hasher);
+        let mut hash: u64 = 0xcbf29ce484222325; // FNV-1a offset basis
+        let fnv_fold = |h: &mut u64, bytes: &[u8]| {
+            for &b in bytes {
+                *h ^= b as u64;
+                *h = h.wrapping_mul(0x100000001b3); // FNV-1a prime
+            }
+        };
+        fnv_fold(&mut hash, &time.tick.to_le_bytes());
+        fnv_fold(&mut hash, &observer_pos.x.to_le_bytes());
+        fnv_fold(&mut hash, &observer_pos.y.to_le_bytes());
+        fnv_fold(&mut hash, &observer_pos.z.to_le_bytes());
         let npc_count = npc_count_query.iter().count() as u64;
-        npc_count.hash(&mut hasher);
-        Some(hasher.finish())
+        fnv_fold(&mut hash, &npc_count.to_le_bytes());
+        Some(hash)
     };
 
     // Drain sim errors collected this tick (#85)