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/Perception/EnemyThreatAssessor.cs

@@ -0,0 +1,54 @@
+using UnityEngine;
+
+namespace BaseGames.Enemies.Perception
+{
+    /// <summary>
+    /// 威胁评估器：在原始 LOS 结果上叠加感知反应延迟，使敌人不会瞬间发现玩家。
+    ///
+    /// 工作原理：
+    /// <list type="bullet">
+    ///   <item>读取 <see cref="EnemyBase.HasLineOfSight"/>（原始 LOS，BatchLOSSystem 写入）。</item>
+    ///   <item>连续感知到玩家超过 <see cref="reactionDelay"/> 秒后，<see cref="IsThreatDetected"/> 才变为 true。</item>
+    ///   <item>一旦丢失 LOS，<see cref="IsThreatDetected"/> 立即重置为 false（保持对"躲起来"的快速响应）。</item>
+    /// </list>
+    ///
+    /// 挂载：添加到与 <see cref="EnemyBase"/> 相同的 GameObject。
+    /// <see cref="EnemyBase.IsPlayerVisible()"/> 会自动路由至此组件（如果存在）。
+    /// </summary>
+    [RequireComponent(typeof(EnemyBase))]
+    public class EnemyThreatAssessor : MonoBehaviour
+    {
+        [Tooltip("持续感知此时长（s）后判定为威胁；模拟敌人的反应时间")]
+        [SerializeField] [Min(0f)] private float reactionDelay = 0.15f;
+
+        private EnemyBase _enemy;
+        private float     _losAccumulator;
+
+        /// <summary>是否已将玩家判定为当前威胁（含反应延迟）。</summary>
+        public bool IsThreatDetected { get; private set; }
+
+        private void Awake()
+        {
+            _enemy = GetComponent<EnemyBase>();
+        }
+
+        private void Update()
+        {
+            if (_enemy == null) return;
+
+            bool hasLos = _enemy.HasLineOfSight;
+
+            if (hasLos)
+            {
+                _losAccumulator += Time.deltaTime;
+                if (_losAccumulator >= reactionDelay)
+                    IsThreatDetected = true;
+            }
+            else
+            {
+                _losAccumulator  = 0f;
+                IsThreatDetected = false;
+            }
+        }
+    }
+}