fix(portal): synchronize destination presentation state

src/AcDream.Core/Physics/AnimationSequencer.cs

@@ -566,9 +566,7 @@ public sealed class AnimationSequencer
         if (_core.CurrAnim == null && rootMotionFrame is null)
             return BuildIdentityFrame(partCount);
         if (dt <= 0f)
-            return _core.CurrAnim == null
-                ? BuildIdentityFrame(partCount)
-                : BuildBlendedFrame();
+            return SampleCurrentPose();
 
         _core.Update(dt, rootMotionFrame);
 
@@ -577,6 +575,19 @@ public sealed class AnimationSequencer
             : BuildBlendedFrame();
     }
 
+    /// <summary>
+    /// Samples the current sequence frame without advancing animation time or
+    /// dispatching hooks. This is retail's hidden-object
+    /// <c>CPhysicsObj::set_frame -&gt; CPartArray::SetFrame -&gt; UpdateParts</c>
+    /// path: <c>HandleEnterWorld</c> may move the sequence cursor from a completed
+    /// link to the cyclic tail, and the hidden object must recompose that new pose
+    /// while PartArray time remains frozen.
+    /// </summary>
+    public IReadOnlyList<PartTransform> SampleCurrentPose()
+        => _core.CurrAnim == null
+            ? BuildIdentityFrame(_setup.Parts.Count)
+            : BuildBlendedFrame();
+
     /// <summary>
     /// Retrieve and clear the list of hooks that fired since the last call.
     /// Empty when no frame boundary was crossed. Safe to call multiple