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/perception/mod.rs

@@ -5,6 +5,7 @@
 use bevy_app::prelude::*;
 use bevy_ecs::schedule::IntoScheduleConfigs;
 
+pub mod cognitive_delay;
 pub mod interpretation;
 pub mod observation;
 pub mod observer;
@@ -23,9 +24,14 @@ impl Plugin for PerceptionPlugin {
             .init_resource::<query::ActivePerceptionMode>()
             .add_systems(
                 Update,
-                interpretation::generate_observation_events
-                    .after(observation::emit_observation_events)
-                    .before(crate::knowledge::events::process_knowledge_events),
+                (
+                    cognitive_delay::process_cognitive_delay
+                        .after(observation::emit_observation_events)
+                        .before(crate::knowledge::events::process_knowledge_events),
+                    interpretation::generate_observation_events
+                        .after(observation::emit_observation_events)
+                        .before(crate::knowledge::events::process_knowledge_events),
+                ),
             );
         tracing::debug!("PerceptionPlugin initialized");
     }