fix(streaming): preserve portal destination ownership

Detach old-world spatial ownership atomically, prioritize destination retirement dependencies, and reveal the viewport at the retail transition edge. Give private paperdoll views independent mesh ownership and retain dormant ACE entities so portal revisits preserve server objects without extending active GPU lifetimes.

src/AcDream.App/Net/LiveSessionRuntimeFactory.cs

@@ -218,7 +218,7 @@ internal sealed class LiveSessionRuntimeFactory
         _world.Hydration.ResetSessionState();
         _player.Shortcuts.Items = Array.Empty<ShortcutEntry>();
         _player.DesiredComponents.Clear();
-        _ui.Paperdoll?.MarkDirty();
+        _ui.Paperdoll?.ResetSession();
 
         // X/Y are ignored until the next logical player CreateObject claims a
         // new origin. Keeping the last values avoids inventing a synthetic