feat(perception): add cognitive delay system for fog recognition (#423)

New CognitiveDelay component buffers perception events before emitting
KnowledgeEvents. Normal delay: 6 ticks (0.6s), urgent: 3 ticks (0.3s).
Drain system runs after emit_observation_events, before process_knowledge_events.

Adds pending_recognitions to ObserverSnapshot (protocol v7) for client
fog entity visualization. Includes cancellation when entity leaves LOS.

Monologue fires during delay (not after) per D-060 — cross-system
wiring deferred to follow-up ticket #451.

Ref: D-060 (cognitive delay), D-031 (10 tps), D-059 (fog layers)

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

server/src/knowledge/events.rs

@@ -79,8 +79,15 @@ pub fn process_knowledge_events(
                 if let Some(stable_id) = registry.to_stable(target) {
                     observer_kg.observe_entity(stable_id, position, event.tick);
                 } else {
-                    debug_assert!(false, "DirectObservation target {:?} not in EntityRegistry", target);
-                    tracing::error!("DirectObservation target {:?} not in EntityRegistry", target);
+                    debug_assert!(
+                        false,
+                        "DirectObservation target {:?} not in EntityRegistry",
+                        target
+                    );
+                    tracing::error!(
+                        "DirectObservation target {:?} not in EntityRegistry",
+                        target
+                    );
                 }
             }
             KnowledgeEventType::LeftLOS { target } => {
@@ -262,7 +269,11 @@ mod tests {
         world.insert_resource(thresholds);
 
         // Tick 7: not a multiple of 10, decay should NOT run
-        world.insert_resource({ let mut t = SimulationTime::default(); t.tick = 7; t });
+        world.insert_resource({
+            let mut t = SimulationTime::default();
+            t.tick = 7;
+            t
+        });
         let mut schedule = bevy_ecs::schedule::Schedule::default();
         schedule.add_systems(decay_knowledge);
         schedule.run(&mut world);
@@ -275,7 +286,11 @@ mod tests {
         );
 
         // Tick 10: multiple of 10, decay SHOULD run (age = 10 > decay_after = 5)
-        world.insert_resource({ let mut t = SimulationTime::default(); t.tick = 10; t });
+        world.insert_resource({
+            let mut t = SimulationTime::default();
+            t.tick = 10;
+            t
+        });
         let mut schedule2 = bevy_ecs::schedule::Schedule::default();
         schedule2.add_systems(decay_knowledge);
         schedule2.run(&mut world);