fix(world): match retail portal passage and exit warp

src/AcDream.App/Rendering/RetailChaseCamera.cs

@@ -247,6 +247,32 @@ public sealed class RetailChaseCamera : ICamera
         PlayerTranslucency = ComputeTranslucency(d);
     }
 
+    /// <summary>
+    /// Retail <c>SmartBox::set_viewer(playerPosition, reset_sought: 1)</c>
+    /// (<c>0x00452C40</c>), called by
+    /// <c>SmartBox::PlayerPositionUpdated</c> after a teleport
+    /// (<c>0x00453870</c>). Both the published viewer and its sought
+    /// position restart at the player; subsequent camera updates then
+    /// re-extend the boom through the ordinary damped/swept path.
+    /// </summary>
+    public void ResetViewerToPlayer(Vector3 playerPosition, float playerYaw)
+    {
+        Vector3 playerForward = new(MathF.Cos(playerYaw), MathF.Sin(playerYaw), 0f);
+
+        _publishedEye = playerPosition;
+        _soughtEye = playerPosition;
+        _dampedForward = playerForward;
+        _initialised = true;
+
+        Position = playerPosition;
+        ViewerCellId = 0u; // retail set_viewer clears viewer_cell at the teleport boundary
+        View = Matrix4x4.CreateLookAt(
+            playerPosition,
+            playerPosition + playerForward,
+            Vector3.UnitZ);
+        PlayerTranslucency = 0f;
+    }
+
     /// <summary>
     /// Adjust the camera distance (zoom) by a delta, clamped to
     /// <see cref="DistanceMin"/>..<see cref="DistanceMax"/>. Mirrors