feat: Implement Room Streaming System

- Add RoomStreamingManager to manage room loading and unloading based on player proximity.
- Create StreamingBudgetConfigSO for memory and performance budgeting of the streaming system.
- Introduce TransitionDirector to handle seamless and atmospheric fade transitions between rooms.
- Develop WorldGraph to represent room connectivity and facilitate neighbor queries and distance calculations.
- Implement RoomNode and RoomEdge classes to structure room data and connections.

Assets/_Game/Scripts/Enemies/AI/BD_WalkRandom.cs

@@ -0,0 +1,44 @@
+#if GRAPH_DESIGNER
+using UnityEngine;
+using Opsive.BehaviorDesigner.Runtime.Tasks;
+using Opsive.BehaviorDesigner.Runtime.Tasks.Actions;
+using BaseGames.Enemies;
+
+namespace BaseGames.Enemies.AI
+{
+    /// <summary>
+    /// 动作：随机游走（调用 NavAgent.SetRandomDestination）。
+    /// 到达目的地后立即选下一个随机点，持续 Running。
+    /// 常用于巡逻 fallback 或无路点的小怪。
+    /// </summary>
+    [TaskName("Walk Random")]
+    [TaskCategory("BaseGames/Enemy/Movement")]
+    [TaskDescription("随机游走：持续选取随机目的地导航（常用于待机巡逻兜底）")]
+    public sealed class BD_WalkRandom : Action
+    {
+        [Tooltip("尝试选取随机点的次数")]
+        [SerializeField] private int m_RetryCount = 5;
+
+        private EnemyBase _enemy;
+
+        public override void OnAwake() => _enemy = gameObject.GetComponent<EnemyBase>();
+
+        public override void OnStart() => TryWalk();
+
+        public override TaskStatus OnUpdate()
+        {
+            if (_enemy == null) return TaskStatus.Failure;
+            if (_enemy.Nav.IsAtDestination()) TryWalk();
+            return TaskStatus.Running;
+        }
+
+        public override void OnEnd() => _enemy?.StopMovement();
+
+        private void TryWalk()
+        {
+            for (int i = 0; i < m_RetryCount; i++)
+                if (_enemy.Nav.WalkToRandom()) break;
+        }
+    }
+}
+#endif