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/Core/Assets/AddressKeys.cs

@@ -51,7 +51,10 @@ namespace BaseGames.Core.Assets
         public const string PrefabWeaponSoulStaff = "WPN_SoulStaff";
 
         // ── Config ScriptableObjects ─────────────────────────────────────
-        public const string DataFootstepCatalog   = "Config/FootstepCatalog";
+        public const string DataFootstepCatalog         = "Config/FootstepCatalog";
+
+        /// <summary>流式加载预算配置 SO，RoomStreamingManager 与 TransitionDirector 均依赖此资产。</summary>
+        public const string DataStreamingBudgetConfig   = "Config/StreamingBudgetConfig";
 
         /// <summary>
         /// Addressable Label 常量（用于批量加载与预热）。

Assets/_Game/Scripts/Core/Events/TransitionType.cs

@@ -1,7 +1,8 @@
 namespace BaseGames.Core.Events
 {
     /// <summary>
-    /// 场景过渡类型，决定 <see cref="BaseGames.Core.SceneService"/> 的演出行为。
+    /// 场景过渡类型，决定 <see cref="BaseGames.Core.SceneService"/> 或
+    /// <see cref="BaseGames.Core.ITransitionDirector"/> 的演出行为。
     /// </summary>
     public enum TransitionType
     {
@@ -12,5 +13,14 @@ namespace BaseGames.Core.Events
         /// <summary>跨大区域切换。完整淡出，显示加载画面。
         /// 适用于地图间传送、返回标题、大区域入口等有明显空间跳跃感的切换。</summary>
         Scene,
+
+        /// <summary>无缝切换。无任何遮挡，目标房间必须已预加载（Dormant 状态）。
+        /// 相机跟随玩家越过边界，视觉上无任何打断感。
+        /// 若目标房间尚未就绪，TransitionDirector 将等待预加载完成后再执行切换（有超时保护）。</summary>
+        Seamless,
+
+        /// <summary>氛围淡入淡出切换。短暂淡出（≈0.25 s）+ 显示新区域名称 + 淡入。
+        /// 适用于跨大区域边界、目标房间已预加载的情况，比 Room 有更强的"抵达感"。</summary>
+        AtmosphericFade,
     }
 }

Assets/_Game/Scripts/Core/ITransitionDirector.cs

@@ -0,0 +1,28 @@
+using BaseGames.Core.Events;
+
+namespace BaseGames.Core
+{
+    /// <summary>
+    /// 过渡导演接口。
+    /// <para>
+    /// <see cref="SceneService"/> 在处理 <see cref="SceneLoadRequest"/> 时，
+    /// 若过渡类型为 <see cref="TransitionType.Seamless"/> 或 <see cref="TransitionType.AtmosphericFade"/>，
+    /// 则通过 ServiceLocator 查找此接口并委托处理。
+    /// 若未找到实现（非流式模式），则退回原有淡出加载流程。
+    /// </para>
+    /// </summary>
+    public interface ITransitionDirector
+    {
+        /// <summary>
+        /// 处理过渡请求。由 SceneService 在确认过渡类型后调用。
+        /// 实现方负责完整的过渡流程（激活目标房间、相机切换、播放演出等）。
+        /// </summary>
+        void HandleTransition(SceneLoadRequest request);
+
+        /// <summary>
+        /// 查询目标场景是否已预加载完毕（处于 Dormant 状态），可执行无缝切换。
+        /// 若返回 false，SceneService 将退回带黑屏的 Room 过渡。
+        /// </summary>
+        bool CanHandleSeamless(string targetSceneName);
+    }
+}

Assets/_Game/Scripts/Core/SceneService.cs

@@ -70,7 +70,29 @@ namespace BaseGames.Core
         private void OnDisable() => _subscriptions.Clear();
 
         private void HandleSceneLoadRequest(SceneLoadRequest request)
-            => StartCoroutine(LoadSceneCoroutine(request));
+        {
+            // Seamless / AtmosphericFade 由 ITransitionDirector 处理（需要预加载支持）
+            if (request.TransitionType == TransitionType.Seamless ||
+                request.TransitionType == TransitionType.AtmosphericFade)
+            {
+                var director = ServiceLocator.GetOrDefault<ITransitionDirector>();
+                if (director != null)
+                {
+                    // TransitionDirector 内部处理"立即切换"与"等待预加载后切换"两条路径
+                    director.HandleTransition(request);
+                    return;
+                }
+
+                // 未注册 ITransitionDirector（非流式模式）：降级为 Room 过渡
+                Debug.LogWarning($"[SceneService] 未找到 ITransitionDirector，{request.TransitionType} 降级为 Room 过渡。");
+                var degraded = request;
+                degraded.TransitionType = TransitionType.Room;
+                StartCoroutine(LoadSceneCoroutine(degraded));
+                return;
+            }
+
+            StartCoroutine(LoadSceneCoroutine(request));
+        }
 
         public IEnumerator LoadSceneCoroutine(SceneLoadRequest request)
         {