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_UseBossSkillWeighted.cs

@@ -0,0 +1,54 @@
+#if GRAPH_DESIGNER
+using Opsive.BehaviorDesigner.Runtime.Tasks;
+using Opsive.BehaviorDesigner.Runtime.Tasks.Actions;
+using UnityEngine;
+
+namespace BaseGames.Enemies.AI
+{
+    /// <summary>
+    /// BD Action：在当前阶段可用且冷却就绪的技能中，按 weight 加权随机选择一个技能并执行。
+    ///
+    /// 返回 Running：技能正在执行。
+    /// 返回 Success：技能执行完成。
+    /// 返回 Failure：无可用技能，或执行器忙。
+    ///
+    /// 用法：在 Boss BT 的 Combat 阶段，替代 BD_UseBossSkill（固定 ID）实现随机化技能组合。
+    /// 每个 BossSkillSO 设置 weight 字段控制出现概率：越大越常见。
+    /// </summary>
+    [TaskName("Use Boss Skill (Weighted)")]
+    [TaskCategory("BaseGames/Enemy/Boss")]
+    [TaskDescription("加权随机选择并执行可用技能；对上一次使用的技能施加权重惩罚")]
+    public class BD_UseBossSkillWeighted : Action
+    {
+        [Tooltip("等待技能执行完成后才返回 Success。关闭后执行开始即返回 Success，BT 继续运行其他节点。")]
+        [SerializeField] private bool m_WaitForCompletion = true;
+
+        private BossBase _boss;
+        private bool     _started;
+
+        public override void OnAwake() => _boss = GetComponent<BossBase>();
+
+        public override void OnStart()
+        {
+            _started = false;
+        }
+
+        public override TaskStatus OnUpdate()
+        {
+            if (_boss == null) return TaskStatus.Failure;
+
+            if (!_started)
+            {
+                bool ok = _boss.UseBossSkillWeighted();
+                if (!ok) return TaskStatus.Failure;
+                _started = true;
+
+                if (!m_WaitForCompletion) return TaskStatus.Success;
+            }
+
+            // 等待技能执行完成
+            return _boss.IsBossSkillExecuting ? TaskStatus.Running : TaskStatus.Success;
+        }
+    }
+}
+#endif