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_CanReachTarget.cs

@@ -0,0 +1,35 @@
+#if GRAPH_DESIGNER
+using UnityEngine;
+using Opsive.BehaviorDesigner.Runtime.Tasks;
+using Opsive.BehaviorDesigner.Runtime.Tasks.Conditionals;
+using BaseGames.Enemies;
+
+namespace BaseGames.Enemies.AI
+{
+    /// <summary>
+    /// 条件：目标坐标从当前位置是否可到达（调用 NavAgent.CanReach，无法寻路时 Failure）。
+    /// 用于 Boss 阶段切换或小怪决策能否追击到跨平台目标。
+    /// </summary>
+    [TaskName("Can Reach Target?")]
+    [TaskCategory("BaseGames/Enemy/Perception")]
+    [TaskDescription("检查 NavAgent 是否可以规划到目标的有效路径")]
+    public sealed class BD_CanReachTarget : Conditional
+    {
+        [Tooltip("检查目标（留空则使用玩家位置）")]
+        [SerializeField] private Transform m_Target;
+
+        private EnemyBase _enemy;
+
+        public override void OnAwake() => _enemy = gameObject.GetComponent<EnemyBase>();
+
+        public override TaskStatus OnUpdate()
+        {
+            if (_enemy?.Nav == null) return TaskStatus.Failure;
+            Vector2 pos = m_Target != null
+                ? (Vector2)m_Target.position
+                : _enemy.PlayerTransform != null ? (Vector2)_enemy.PlayerTransform.position : Vector2.zero;
+            return _enemy.Nav.CanReach(pos) ? TaskStatus.Success : TaskStatus.Failure;
+        }
+    }
+}
+#endif