refactor(world): extract live entity hydration

src/AcDream.Core/Items/ClientObjectTable.cs

@@ -576,7 +576,10 @@ public sealed class ClientObjectTable
     /// Atomically replaces the retained qualities for a newer server object
     /// incarnation while publishing a generation-specific teardown event.
     /// </summary>
-    public ClientObject ReplaceGeneration(WeenieData data, ushort generation)
+    public ClientObject? ReplaceGeneration(
+        WeenieData data,
+        ushort generation,
+        Func<bool>? canInstallReplacement = null)
     {
         RemoveCore(
             data.Guid,
@@ -584,6 +587,13 @@ public sealed class ClientObjectTable
             generation,
             notifyObjectRemoved: true);
 
+        // Removal observers may synchronously accept a newer CreateObject for
+        // this GUID. The outer generation must not resume and merge its stale
+        // qualities into that replacement. The authoritative live-identity
+        // owner supplies the exact-incarnation predicate.
+        if (canInstallReplacement?.Invoke() == false)
+            return null;
+
         return Ingest(data);
     }