Protect changing goalSelector to a single server thread, to prevent crash

src/main/java/com/owlmaddie/goals/EntityBehaviorManager.java

 package com.owlmaddie.goals;
 
+import com.owlmaddie.network.ServerPackets;
 import net.minecraft.entity.ai.goal.Goal;
 import net.minecraft.entity.ai.goal.GoalSelector;
+import net.minecraft.entity.ai.goal.PrioritizedGoal;
 import net.minecraft.entity.mob.MobEntity;
 import net.minecraft.server.world.ServerWorld;
-import net.minecraft.entity.ai.goal.PrioritizedGoal;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -37,9 +38,12 @@ public class EntityBehaviorManager {
         List<Goal> goals = entityGoals.computeIfAbsent(entityId, k -> new ArrayList<>());
         goals.add(goal);
 
+        // Ensure that the task is synced with the server thread
+        ServerPackets.serverInstance.execute(() -> {
             GoalSelector goalSelector = GoalUtils.getGoalSelector(entity);
             goalSelector.add(priority.getPriority(), goal);
             LOGGER.debug("Goal of type {} added to entity UUID: {}", goal.getClass().getSimpleName(), entityId);
+        });
     }
 
     public static void removeGoal(MobEntity entity, Class<? extends Goal> goalClass) {
@@ -47,6 +51,8 @@ public class EntityBehaviorManager {
         List<Goal> goals = entityGoals.get(entityId);
 
         if (goals != null) {
+            // Ensure that the task is synced with the server thread
+            ServerPackets.serverInstance.execute(() -> {
                 GoalSelector goalSelector = GoalUtils.getGoalSelector(entity);
                 goals.removeIf(goal -> {
                     if (goalClass.isInstance(goal)) {
@@ -56,10 +62,13 @@ public class EntityBehaviorManager {
                     }
                     return false;
                 });
+            });
         }
     }
 
     private static void moveConflictingGoals(MobEntity entity, GoalPriority newGoalPriority) {
+        // Ensure that the task is synced with the server thread
+        ServerPackets.serverInstance.execute(() -> {
             GoalSelector goalSelector = GoalUtils.getGoalSelector(entity);
 
             // Retrieve the existing goals
@@ -90,5 +99,6 @@ public class EntityBehaviorManager {
                 // Increment the priority and re-add the goal
                 goalSelector.add(goalToModify.getPriority() + 1, goalToModify.getGoal());
             }
+        });
     }
 }