WIP Make static collections thread-safe using ThreadStatic and ThreadLocal

Refactored various static and instance collections to use [ThreadStatic], ThreadLocal, or local variables to prevent concurrent modification issues during parallel updates. This affects status effect targets, affliction lists, damage modifiers, and cached data in Character, CharacterHealth, Limb, Explosion, Hull, Submarine, and ToolBox classes. Also replaced Dictionary caches with ConcurrentDictionary where appropriate for thread safety.

Barotrauma/BarotraumaShared/SharedSource/Map/Hull.cs

@@ -6,6 +6,7 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Threading;
 using System.Xml.Linq;
 using Barotrauma.MapCreatures.Behavior;
 using Barotrauma.Items.Components;
@@ -1133,13 +1134,18 @@ namespace Barotrauma
         }
 
         /// <summary>
-        /// Used in <see cref="GetApproximateDistance"/>
+        /// Used in <see cref="GetApproximateDistance"/> - ThreadLocal for thread safety
         /// </summary>
-        private static readonly Dictionary<Hull, float> cachedDistances = [];
+        private static readonly ThreadLocal<Dictionary<Hull, float>> cachedDistancesLocal = 
+            new ThreadLocal<Dictionary<Hull, float>>(() => new Dictionary<Hull, float>());
         /// <summary>
-        /// Used in <see cref="GetApproximateDistance"/>
+        /// Used in <see cref="GetApproximateDistance"/> - ThreadLocal for thread safety
         /// </summary>
-        private static readonly PriorityQueue<(Hull hull, Vector2 pos), float> priorityQueue = new PriorityQueue<(Hull hull, Vector2 pos), float>();
+        private static readonly ThreadLocal<PriorityQueue<(Hull hull, Vector2 pos), float>> priorityQueueLocal = 
+            new ThreadLocal<PriorityQueue<(Hull hull, Vector2 pos), float>>(() => new PriorityQueue<(Hull hull, Vector2 pos), float>());
+        
+        private static Dictionary<Hull, float> cachedDistances => cachedDistancesLocal.Value;
+        private static PriorityQueue<(Hull hull, Vector2 pos), float> priorityQueue => priorityQueueLocal.Value;
 
         /// <summary>
         /// Approximate distance from this hull to the target hull, moving through open gaps without passing through walls.