[AI] Behavior Actions 시스템 추가

Ultraworked with [Sisyphus](https://github.com/code-yeonggu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/Scripts/AI/BehaviorActions/Actions/StopMovementAction.cs

@@ -0,0 +1,24 @@
+using System;
+using Unity.Behavior;
+using UnityEngine;
+using Action = Unity.Behavior.Action;
+using Unity.Properties;
+
+[Serializable, GeneratePropertyBag]
+[NodeDescription(name: "StopMovement", story: "이동 정지", category: "Action", id: "1a0e2eb87421ed94502031790df56f37")]
+public partial class StopMovementAction : Action
+{
+
+    protected override Status OnStart()
+    {
+        UnityEngine.AI.NavMeshAgent agent = GameObject.GetComponent<UnityEngine.AI.NavMeshAgent>();
+        
+        if (agent != null)
+        {
+            agent.isStopped = true;
+        }
+
+        return Status.Success;
+    }
+}
+