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/bridge/types.rs

@@ -15,7 +15,7 @@ pub use crate::simulation::time::{DayPhase, TickRate};
 /// negotiation is unnecessary. Client should reject snapshots with version !=
 /// PROTOCOL_VERSION. New fields use #[serde(default)] only during the migration
 /// period, then the default is removed once both sides are updated.
-pub const PROTOCOL_VERSION: u8 = 6;
+pub const PROTOCOL_VERSION: u8 = 7;
 
 /// The ONLY data structure crossing the client-server boundary (D-020)
 /// Contains all information visible to the observer at a given tick.
@@ -25,6 +25,7 @@ pub const PROTOCOL_VERSION: u8 = 6;
 /// v4 adds: nearby_interactions (D-060, #404 proximity + verbs[]).
 /// v5 adds: current_monologue (#414 internal monologue pipeline).
 /// v6 adds: player_stance (#449, D-053), player_inventory (#449, D-065).
+/// v7 adds: pending_recognitions (#423, D-060 cognitive delay).
 /// Future fields: ambient sound events, HUD state (D-020 expansion).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ObserverSnapshot {
@@ -56,6 +57,11 @@ pub struct ObserverSnapshot {
     /// None when no monologue is triggered. Client shows text and auto-fades.
     #[serde(default)]
     pub current_monologue: Option<MonologueEvent>,
+    /// Entities undergoing cognitive delay recognition (#423, D-060).
+    /// Client renders these as grey blobs at position until recognition completes.
+    /// Empty when no recognitions are pending.
+    #[serde(default)]
+    pub pending_recognitions: Vec<PendingRecognitionWire>,
 }
 
 /// Game time data for client display (D-031)
@@ -382,6 +388,23 @@ pub enum VerbKind {
     ExamineObject,
 }
 
+/// A recognition pending cognitive delay, included in ObserverSnapshot (#423, D-060).
+/// Client renders entity as grey blob at position until recognition completes.
+/// Visual transition: grey blob -> D-033 color + silhouette over ~0.3s.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PendingRecognitionWire {
+    /// Wire entity ID (may match entity_id in VisibleEntity if also in entities list)
+    pub entity_id: u64,
+    /// Render position
+    pub x: f32,
+    pub y: f32,
+    pub z: i32,
+    /// Remaining ticks until recognition completes (for progress animation)
+    pub remaining_ticks: u64,
+    /// Total delay for this recognition (for animation timing)
+    pub total_delay_ticks: u64,
+}
+
 /// Internal monologue event sent to the client for display (#414).
 /// Contains the text and display duration. Client auto-fades after duration.
 #[derive(Debug, Clone, Serialize, Deserialize)]